In the early morning, deer wander near the spring-fed pond where blue-gills swim, and red foxes sometimes can be seen darting around the six arces of woods on the hillside.

At the top of the hill sits a 50-by-60-foot rough-sawn cedar building. Inside, the peace of the pastoral seeting disappears as Jackie Cassello, 13, goes through the rigorous practices she hopes will land her a spot on the U.S. women's Olympic gymnastics team.

The building houses the gym Greg and Margie Weiss built in a remote Corner of Silver Spring to instruct their MG Gymnastics club students, now numbering about 70 youngsters.

High on the wall is an official poster of the 1980 Moscow Olympics.

"Every once in awhile, I do look up at it," admitted the 74-pound Cassello, who says she is "4 feet 9 1/2 inches."

She has just returned with the U.S. national team from an international meet in Bulgaria, where she took first places in the vault, and uneven bars and picked up a prize for the most original bar rountine.

A member of the 1979 Pan American Games gymnastics team, Cassello has accumulated dozens of U.S. and international honors in gymnastics. Now she is shooting for the biggest prize of all, a spot on the Olympic team.

Toward the goal, Cassello has moved in with the Weiss family so she can receive the special coaching attention she needs to perfect her routines.

Cassello had been a live-in student at the Connecticut gymnastics school run by Muriel Grossfeld, but was unhappy there. Living with Greg and Margie Weiss, and their three childre, "is a lot nicer and they care about you," she says.

"The drive for a gymnast has to be greater than anything else," says Margie Weiss. "Some kids just can't leave their parents, and I don't even know if I could let my kids go.

"But Jackie knew that when she came here she was going to be part of a family, which is definitely different from living in a dormitory."

It's a lot different, says Cassello, who telephones her family in South Hempstead, N.Y., every three days and goes home to vist as often as possible.

At her home away from home, she can swim, dive and fish for bluegills in the pond, window-shop in town - a favorite pastime - and ride horses at a teammate's nearby farm.

When she has time, which is not often.

"I get up a 7 a.m., leave for (Farquhar Middle) school at a quarter of eight," she says. "I have school from 9 to 12:15. Then I come back home, eat lunch and do homework until 2:30.

"Then I work out till 8:30 or 9 (taking a break for dinner), do some more homework and go to sleep at 10 or 10:30. Except Wednesday, that's my day off."

Her gymnastics career began, she says, "Because my mom used to be a gymnast in England, so when I was little, she started me on the basic skills and I liked it."

How good are her chances to make the U.S. Olympic team?

"She's very good, but a lot of it will really depend on how hard she works in the next 10 months," says Greg Weiss, a member of the 1964 U.S. Olypic gymnastics team.

"She's a very strong little girl with a very good sense of kinesthetics. She has an ability to make midair corrections . . . She has the talent, but she'll have to polish up on elegance so she doesn't look like a child, but a young lady . . ."

Cassello shows none of the awkwardness of early adolescence as she poses on the balance beam for a photographer. Despite the braces, the smile is wide, the head turned confidently toward the camera.

And there is another sign of sophistication beyond the years. Although she wants to make the Olympic team, Cassello says, she sets intermediate goals, taking one step at a time.

"It's hard to set (Olympic) goals now in case you get hurt," she says.

On the other hand, life without gymnastics is difficult for her to fathom.

"I've been doing it for five years," she says. "It would be hard to stop. I wouldn't know what to do." CAPTION: Picture 1, Gymnast Jackie Cassello, 13, has secluded herself in Silver Spring woods to hone her skills for a bid a berth on the U.S. Olympic team. By Margaret Thomas - The Washington Post; Picture 2, Jackie Cassello