Last fall, seniors at The Holton-Arms School embarked on an adventure in writing undertaken by 20 years of seniors before them. "Write about the experiences of your life," said Sally Alexander, in her 34th year of teaching English at this private girls' school in Bethesda. "Use telling facts." It was the perfect assignment, forcing the girls to take stock as they prepared to take leave, collaring some of their anxieties as they sought solace in patterns.

Maddy Goodman, one of Alexander's pupils, wasn't sure what to make of the assignment at first. A petite young woman with fair skin and chin-length brown hair, she has always kept her own counsel. "She didn't exactly say, `Whee! I get to write about me!' " Alexander recalls.

Yet as the semester unfolded, so did Maddy's memories. As Maddy graduates from high school this week, bidding farewell to childhood, she leaves behind written fragments of events and people who have nudged her forward by helping her make sense of what has been a privileged, if not always easy, life. The excerpts printed throughout serve as a reminder that graduation is gradual: From the time our children come to us, they are preparing to leave. At least the lucky ones are.

When I was seven years old, our back porch caved in. Amid all the construction to rebuild it, my mom finally said I could have a treehouse. After the porch was finished, the workmen would build and paint the little house for me. . . . I formed a club with four of my friends. We named ourselves The Fruit Roll-Up Club. We'd meet every Tuesday, and every time a different member would bring the fruit roll-ups. . . .

The house was built around a tree. The walls were bright white and the roof had green shingles.

Maddy moved into her brick home in Bethesda when she was 4. The wooded lot, which rolled down into Seven Locks Elementary School, provided her and her new pals all kinds of places to hide. Still, as she finished first grade, she nagged her mom for a place where she and her friends could do things away from adult eyes.

Fortunately for Maddy, her parents, Martha and Nelson Goodman, believe kids should be encouraged to chart their own course as age and maturity allow. A speech pathologist to children with severe disabilities, Martha had the simplest of goals for her daughter: "That she be able to walk and talk and read. Everything else was up to her."

The treehouse was created in two days. "I liked how it was really small, proportioned to how small we were," Maddy recently recalled. "It was our place. Grown-ups never came there."

Martha was surprised that Maddy chose to write about the treehouse. "She really didn't spend that much time in it," Martha says. "You think you know what's important to your kids, but you don't."

By the time I was in fifth grade, (the treehouse) smelled of dirt and mildew. Cobwebs hung in every corner and leaves scattered the floor. It was during the spring that I was in my clubhouse after school one day, alone with my friend Adam. And it was there that he kissed me, my first kiss. It was on the cheek, of course, and afterward I started to giggle, like someone in a movie. His breath had smelled like a Hersey bar.

Maddy sailed through Seven Locks Elementary "until fifth grade," Nelson remembers. "Then she got involved socially, caring more about what this girl said, that boy said."

Children frequently discover their first private affections as elementary school draws to a close. But Adam, a fifth-grader like Maddy, was too socially precocious for the Goodmans. On Valentine's Day he sent Maddy roses in a crystal vase. He also liked to buy clothes for her. Nelson and Martha decided that her little crowd was trying to grow up too fast.

"Nelson said find her a convent," Martha says with a twinkle in her eyes, "and Holton was the best we could do."

When I was in the eighth grade, I couldn't imagine a day without Nida. . . .

One Friday in mid-November, I went home with Nida after school. By the time we arrived, Nids and I were in hysterics over a man we had seen in a green Volkswagen picking his nose. . . . I glanced down at the papers on Nida's desk. I looked at some of their return addresses: Deerfield Academy, Choate Academy, Exeter. Boarding schools. "What are these?" I demanded . . .

"My mom is making me apply to some boarding schools. . . . "

Nida, our three other best friends, and I went out to dinner for the last time before Nida's departure. . . . When we got back to my house . . . We looked around at each other's sad faces as we talked about how awful Nida's new school would be and how dirty Puerto Rico was, trying to see who would cry first.

Although she had lost friends before, no departures were as keenly felt as Nida's. Nida, whose parents were divorced, was more worldly than Maddy. Maddy had learned to loosen up with her. Once Nida left, Martha says, Maddy "had to reinvent herself all over again."

Maddy had seen how personalities can alter with time. On a trip to Washington State when she was about 11, her family had visited a friend whom Maddy remembered with fondness from earlier visits. Maddy and her younger brother, Eli, decided the woman had changed, and not for the better. Would the same thing happen with Nida?

Maddy's parents made sure Nida visited them on holidays and during the summer; and Maddy also flew to Nida's home in Puerto Rico. "It's really surprising," Maddy says, "she hasn't changed that much. We're still the same when she comes."

The water was dark grey, opaque, like we were floating in a vat of paint. As the old metal rowboat sliced cleanly through Spa Creek, my eyes absently followed the trees on the nearby shore. . . .

"Hey," Will said, offering me a cigarette from a rumpled white box. I shook my head and watched as he fumbled with the lighter. . . .

"So you're going to St. Mary's next year?" I asked him, though I already knew the answer. . . .

I sat on the green and white plaid couch, Teddy to my right and Will to my left, as we watched "A Christmas Story." . . . I glanced down at the framed picture on the coffee table in front of me. It was taken on the Christmas when the boys were five and I was four. We had stood in a line wearing our new Superman pajamas and clutching our new Care Bears. . . .

Maddy has always loved spending Christmas evening with family friends in Annapolis, particularly the ritual of decorating gingerbread houses with the twins, Will and Ted. "It used to be my absolutely favorite thing to do," she says.

Will's and Ted's family, and four or five other families who are part of the Goodman circle, have provided Maddy with places she belonged. "Our friends are her friends, too," says Nelson Goodman, an endodontist. She can leave them, as she will soon leave home, knowing she can always return to people to whom she "doesn't have to prove anything."

Maddy also has been lucky to know several adults to whom she did have to prove something. These included Holton's Alexander, Suzanne Friedman, a violin teacher, and Kathe Williamson, a Holton teacher who turned her on to Latin. "Intellectually, Maddy is ready to take off," Williamson says.

"This has been the most amazing day," Petey whispered. I sat in front of him on a bench at the end of the boardwalk, his arms surrounding me from behind, my hands surrounding his arms. We looked out on the dark waves in front of us. . . .

"It's like we were married or something. . . . I mean, we drove here by ourselves, we were alone the whole day, we even went to the supermarket!"

Our house, which everyone said looks like a Pizza Hut, was across the street from the end of the small boardwalk. . . . My mom was sitting on one of the coral pink couches reading a book . . .

"Peter, you can stay in the blue room downstairs. Just put your sleeping bag on one of the beds. . . . "

As I was brushing my teeth . . . I heard someone whisper loudly, "Maddy!"

I peeked outside. There was Petey in his navy and red flannel pajamas, his green eyes wide and urgent. "What is it Peets? It's against the rules for you to be upstairs."

"Maddy, listen, I can't sleep downstairs. I'm all alone . . . and it's dark. . . . "

He knocked on the door of the master bedroom. . . . "Mrs. Goodman," he said, examining his bare toes, "is there any way I could sleep upstairs?"

A violent winter storm destroyed Maddy's treehouse during her junior year. Watching workmen cart away the little house the morning after the storm, "I was in shock," she recalls. "It symbolized a lot of first things. Now I'd have to . . . " Her sentence hangs in the air unfinished -- too scary to finish, perhaps, as she anticipates graduation and entering Duke University in the fall.

Academically speaking, senior year has been a breeze compared with junior year's AP biology, AP Latin and pre-calculus. Socially it has been tougher because of a couple of slights from people she trusted. Her mother has told her these woundings show that "it is time to move on and moving on will be good."

Her true anchor has been a tall, good-looking guy named Petey McTernan, who has a pierced tongue, two earrings and two four-inch-high angels tattooed in bright colors around his left ankle.

Petey graduated last week from Walt Whitman High School. "We're really good friends," she says.

Martha Goodman remembers her surprise when she first met Petey. "I spend my days teaching kids to talk and there he was with his tongue pierced," she says.

But she and Nelson liked his good manners and friendliness. Perhaps most important, Maddy was "completely herself with him and he adored her," Martha says. "They're bringing each other up."

Martha still chuckles over Petey showing up scared at her beach house bedroom door. "They want to do all the grown-up stuff but call on us when they need us," she says.

In two days, Maddy's emancipation will be final. Driving back from her last Spanish lesson, she teases her friend Claire Zietz that she will forgo mascara for the ceremony and wear sunglasses to hide her tears.

"My mom will be crying and that'll start me crying," she explains.

Martha suspects that she may indeed cry, but not for long. There are lots of seniors out there who, for economic and other reasons, will not be going to college.

"We are fortunate to be able to send her off," she says. "Sad is not having this happen."

CAPTION: Maddy Goodman, center, with her father, Nelson, mother, Martha, friend, Petey McTernan, and brother, Eli, at home before heading to her prom last Saturday night.

CAPTION: Holton-Arms senior Maddy Goodman playing in a lacrosse game last month against Georgetown Visitation.