THIS IS my last year of celebrated adolescence. I'm a senior at Bethesda-Chevy Chase High School. Next year I'll be in college -- away from my family. I'm what my English teacher calls "an inner-Beltway child." He maintains that we middle-class children cannot relate to the main character of "Heart of Darkness." But I am stubborn. I can imagine the savagery of a jungle and a civilized man's feelings as he becomes aware of his inner ties with a primitive culture. It is in this classroom that I have been exposed to a variety of works. Here, I have sat through the reading of Beckett's "Waiting for Godot," I have listened to a discussion of "The Absurdity of Aubrey Beardsley," and contributed to a debate concerning the innocence of Tess of the D'Urbervilles. (I didn't sympathize with her.)

In calculus class, I watch a red-haired, bearded man miraculously construct three- dimensional shapes on a two-dimensional blackboard and I struggle (in vain) to do the same on my paper. He uses multicolored chalk, which forms murky blotches on the back of his jacket where he leans against the board. He is our senior class sponsor as well as our teacher. This year, he explains, we cannot wear caps with cardboard insets for our graduation at the Kennedy Center. It seems that at last year's ceremony, chandeliers were broken and some unfortunate individual suffered a lacerated skull as the result of overzealous cap-throwing. We must now purchase "soft" caps, made of "nerf-ball" material. They droop and wilt, we all complain. But "hard" caps have been outlawed. Continuing, my tacher draws a geometric figure on the board. He tells us that it is a TESO -- a new term for me and confusion sets in as I'm sure it was not presented in the chapter. A TESO is what the book termed a frustrum. So where did he get TESO.? Oh, I see . . . a TESO is the Thing Elephants Stand On. This is the same teacher who lends me his coat when he sees that I'm suffering from the lack of lack of heat in the classroom.

I saw a squirrel run down a tree while I waited for the light at Reno and Western. He stopped. I wished the light would not change.

Physics. The teacher delights in watching our faces change from slight bewilderment to extensive confusion. But there is pure, untainted pleasure in the realization that Eemc2 is a reasonable statement. And the most humorous performance I've seen in a long time was staged in physics class. With a student reluctantly attached to a whirling, crackling Van de Graaff generator, we looked on as his hair literally stood on end. I was crying with laughter. After a while, some of us more curious students tried to experience this new sensation ourselves. As we converged on the machine, there was a lone, loud crack and the lucky student who had been guinea pig in this experiment found sparks flying from his fingertips. We had short-circuited the operation, we were told, as the slightly shocked student's hair returned to its natural position.

I brought a snowball into the cafeteria once and let it melt in my hand.

I am working as an intern in a physical chemistry lab at the National Institutes of Health. I'm struck by the disorganization in the laboratories. I can see where the stereotype of the forgetful scientist originated. Free counter space is not abundant. The tables are cluttered with unlabeled beakers and full test tube racks. Telephone messages are often written on the walls. Most of the calendars are not turned to the correct month and some are not even of the correct year. It's fabulous to work with such people. Stubborn child that I am, it still seems inconceivible to me that life is ruled by such rigid laws as PVenRT. Although I accepted these ideas as I learned them in school, the classroom is seemingly isolated from the "real world." I am uncomfortable cat the sight of a periodic chart in a chemistry lab. Yes, it is the most logical place to find one, but do chemists really rely on a chart of numbers? (They sure do.)

Girls, discussing clothes in Latin class, divulge their refusal to weaar hand-me-downs. And a boy exposes his socks with alligator logo to everyone's approval. But I am too adamant in my rebellion against preppiness. First consideration when shopping: Could this be viewed as preppie? If so, I reject it immediately.

In Mrs. Alberts' opinion, nothing is more beautiful than a cat skeleton. But Jill disagrees; she loves her cat.

I visited my elementary school. They don't have walls anymore. The floors are carpeted and the water fountains are knee-high. They have a gymnasium, typewriters, computers and video equipment. And a choir. And they don't play kissing-cooties anymore. Bomb scare and appropriate evacuation were on Wednesday's agenda.

Chevy Chase. Living nextdoor to a couple with two Mercedes. Their entire winter is spent in Florida; then, after returning for a week, it's off to Honolulu. It would be appreciated if we would watch the house while they're away -- report any seedy-looking characters who might be about, keep an eye on the maid and the gardener (one can never be sure, you know), and, of course, if the burglar alarm goes off (usually a 2 a.m. occurrence), be sure to give the house key to the police. Walking the dog through the Columbia Country Club grounds in my "anti- preppie" clothes, I am given unwelcoming glances. I applied here for a lifeguarding job. The man I had talked to, who I later found out was director of aquatics, told me that he was not associated with the club. There ended any future country club employment for me.

On Quincy Street, a tree stands in the center of the sidewalk. A triple hex on any girl who dares to walk around the boys' side. Or vice versa . . . I suppose.

I don't want to grow up. I want those days when my biggest worry was that the principal might find out who let the wet dog into the school. Yesterday, I asked my father if abortions were legal in Colorado. He asked if I had a problem. It hadn't occurred to me that he would assume that I was referring to myself. I suppose I am almost an adult whether I like it or not. If I were a boy, I would be worrying about the draft . . .