Biting her lip and lowering her chin as the giggles overtake her, Donna Ashlock looks like what she is: a 14-year-old girl her mother describes as "kind of shy."

But she is also the star of a drama so sensational it seemed a supermarket tabloid's dream story. Donna Ashlock is the recipient of the transplanted heart of a 15-year-old friend who predicted his own death and asked for his heart to go to her.

"There was one picture of me right after the operation," says Donna as she giggles and squirms her way through another session with a photographer. "I was hooked up to the machines -- I don't know how it got out. And my father brought it here with him! He keeps taking it out!"

The pale face covered with pale freckles twists into a grimace.

Donna Ashlock is now well, healthy enough to groan and complain. But two months ago she lay in a hospital in San Francisco, dying from an inflamed heart and waiting for a suitable transplant donor. A boy she knew from her small home town of Patterson, Calif., Felipe Garza Jr., endcol had a crush on her. And soon after telling his family that if he died, Donna should receive ld,10 sw,-2 sk,2 his heart, he collapsed and within hours was dead from a burst blood vessel.

The transplant operation followed. So did the reporters. One version of the story followed another -- Donna and Felipe were dating; Donna and Felipe were not dating. And as it all unfolded in articles describing Donna as the girl "with the heart of a young admirer beating in her chest," the movie offers, the letters from strangers and the television cameras started to come. The National Enquirer wanted to buy her story, as did a number of movie production companies.

And now there is a visit to Washington, where Donna will be the guest of honor at an American Heart Association ball Friday, and where she went to the White House yesterday to meet with President Reagan, who gave her a jar of jellybeans and a bud vase with Nancy Reagan's signature.

"For the Heart Association and donor program, it's great," says Donna's father Raymond Ashlock during lunch at the J.W. Marriott. "But for us, it's different."

Very different. Raymond Ashlock, public works supervisor in Patterson, a town of 5,000 he describes as "itty-bitty," looks worn out after only his second day of the five-day visit to Washington. He looks warily at the pa te' he has been encouraged to taste for the first time and talks eagerly about the nap that would follow an appearance on "Live at Five." The White House, Raymond Ashlock says, was beautiful, and their first trip to Washington very exciting. But Mary Ashlock, wearing a new black and pink dress donated by a local store where she and her daughter went shopping yesterday morning, has the same tired look around the eyes as her husband.

Donna, who will receive a new long dress ("probably something hot pink -- her favorite color") for the Friday night ball, would rather just wear jeans.

"That's all we wear at home," she says, with a roll of the eyes. "Jeans and sweat shirts. You can get 501s in pink, you can get them in any color."

Ball chairman Steve Varsano, who thought of inviting Donna and her parents to Washington, says, "It just seemed a touching type of a story. Usually people just go to a benefit and they don't know too much about what their money is going to. This is real life -- see and touch and feel what your money is really paying for."

And while the ball guests get Donna Ashlock, the Ashlocks get an all-expense-paid trip to Washington for three. Donna's pediatric cardiologist, Andrew Fryer, and his wife Sally, Donna's physical therapist, were also brought to Washington. Donna is well enough to travel on her own, but Andrew Fryer is good at providing the medical information reporters want. And, as he smiles and explains and responds to Donna's cracks about his request that she cut back on salt and cholesterol, he deflects some of the attention from the weary Ashlocks.

"The coincidence is phenomenal," says Fryer, who practices in San Francisco. "Just to have two kids have this kind of event in the same town -- the odds are incredible. For the two of them to know each other is more incredible. And for the events to follow . . . " He doesn't get specific about the events -- no one seems to want to get too specific about Felipe's death.

"It'll probably never happen again in history," says Raymond Ashlock quietly.

Donna, who has learned to ignore discussions like this, just as she ignores the discussions of her "adrenal function," doesn't look up from her food. In her pink pants, pink blouse and pink vest (her pink scarf and pink jacket are nearby) she avoids most questions with giggles or an "I don't know" and has to be coaxed by a woman doing public relations for the ball to do one more television interview -- "Just a quickie. Really."

The coincidences that so captured people's imaginations have brought the reluctant interview subject more than 200 letters.

"Now all they need to do is send them to Donna Ashlock, Patterson, California," says her mother.

"No address, nothing!" says her father. "They go right to her."

"There was the guy from prison," says Donna. "He had a dream."

But the prisoner's dream, like Donna's relationship with Felipe, is another thing Donna does not want to discuss.

"He was really nice, he really was," Mary Ashlock says, but across the table Raymond shakes his head.

"Weird!" he says.

And then there are the reporters. Writers have gotten some things wrong?

"Gotten wrong?" He laughs. "They just put it in, gotten it off the walls or something."

But, says Mary, "the newspaper people have quieted down."

Donna sniffs derisively.

"Well, it's not as bad," her mother offers.

"It's either calmed down," says Raymond, "or we're used to it."

Clearly the hope is that someday soon the Ashlocks won't just have to be used to it. Donna is scheduled to return to ninth grade next week. Last week she returned to her after-school job at the Tiger Den, working the cash register for two hours. The two other Ashlock children, Chuckie, 16, and Tracy, 12, are back in Patterson, going about their lives, as is Donna's grandmother, who Donna is sure will take one look at her jar of jellybeans and bud vase and "rip them off so fast -- she'll say, 'It'll look so nice on my shelf.' "

"It was really hard for the whole family," says Mary Ashlock. "They were scared when they found out she'd had a heart transplant, but they realized if she didn't, she wouldn't be here today."

And of Felipe, whom neither of the Ashlocks knew -- "It was upsetting, but yet it was nice, to hear it was one of her friends."

She has said this so many times before, but she still looks seriously at the questioner and says slowly, "And we're very grateful. That's for sure."

She looks at her daughter, who has removed her hamburger from the roll and is eating a bacon, pickle and mayonnaise sandwich (pickles and mayo is her favorite sandwich). "Even now," Mary Ashlock says, "she looks so good. It's kind of hard to believe she had it done."