Among the 18,000 spectators at the final night of the women's Olympic gymnastics competition in Montreal last July was a 13-year-old Bathesda girl.

Sitting in the upper deck, she provided a running commentary to her father, spotting a performer who mistimed her [WORD ILLEGIBLE] or another who executed an aerial vault without a flaw. And she imagined herself down there on the floor.

The girl was Stephanie Willim, who made it down there on the floor in the America's Cup gymnastic exhibitions this month at Madison Square Garden in New York. By all indications she stands a good chance for the 1980 Olympics. The evation in Madison Square Garden for her performance was enough for the officials to call her back for an encore.

Last month she was one of 10 girls named to the U.S. Junior Elite gymnastic team. Formed by the United States Gymnastics Federation last fall, the team will train for the 1978 World Games and 1980 Olympics in an effort to become more competitive with teams of Europe and the Soviet Union.

"She's a remarkable child, though I hesitate to refer to her as a child," said Edward Conisty, technical director of the Gymnastics Federation. "She moves like an adult.She's still very young and I'm not sure she would have been ready for Montreal, but if all goes well, she should be ready for the World Games in France."

However, Conisty points out the major obstacle that Stephanie, who is ranked third on the team behind two 14-year-olds, will have to surmount.

"No matter how good she is," he said, "she is American, and there is a preconceived notion that we are not on a level close to the Romanians or Soviets. We hope the Junior Elite program will provide the experience for our younger kids, but also it's aimed at giving them the publicity they'll need to let the judges and the world know just how good they are."

Stephanie's appointment to the Junior Elites was the reward for three years of concentrated work and specialized training - six-hour-a-day practices, six days a week. She enjoys North Bethesda Junior High, and she is an honor roll seventh-grader, but she likes gymnastics most and the thing she wants most is to go to the Olympics.

"It's what I'm hoping for . . . I'd really like to be able to go," said the 4-foot-5, 63-pounder with a grin.

Just four years ago, Stephanie entertained no thoughts of the Olympics at all. She had a 50 per cent loss of hearing in one ear. School was not easy for Stephanie and at home she grew increasingly restless. Doctors said she was hyperactive.

That summer, when she was 8, Stephanie's parents enrolled her in a Saturday gymnastics program sponsored by the YMCA and it quickly became clear that gymnastics was the outlet she needed. In a few weeks she impressed her instructors so much they recommended specialized training.

"We were downright stunned about her talent in gymnastics at first," recalled her mother, June. "Looking back, it was just one of those things when you hit the right combination - the right sport and the right coaches."

The right coaches turned out to be Marge and Greg Weiss, who, after getting married in 1970, built a 50-by 70-foot gymnasium in their back yard in the outskirts of Silver Spring. The result was MG Gymnastics, which now trains some 150 children ranging from age 3 to age 16.

"Stephanie came to us when she was nine," recalled Greg, a member of the 1964 U.S. gymnastic team and a gold medal winner in the 1964 Pan American Games. "In about 10 minutes I realized that she had a tremendous amount of talent. She couldn't even do a back handspring but I could see that she had an excellent kinesthenic sense and a very solid little frame.

"Mrs. Willim was concerned at first that we take extra care with Stephanie because of her hearing," he continued. "But it was just never a problem. She is so intelligent and coordinated that she could pick up anything she might have missed by seeing us signal or just by feeling out the situation instinctively."

Stephanie progressed at an increasingly fast rate. After six months she had surpassed the "B" team level at MG and in another two months, the "A" team.

"Some people might think that Stephanie is pushed," said Marge Weiss. "She pushes us. She has a tremendous amount of energy, a lot of inherent talent and a lot of drive. She never lets up in practice. You can't be as dedicated as she is without wanting it inside yourself."

Stephanie is often detained after meets to sign autographs these days, but appears to have handled her success well.

"She's never been permitted by her coaches to show off," said Mrs. Willim. "But she's never been that type of girl anyway. She takes everything in stride, whether it's success or whether she's messed up one of her stunts."

Stephanie's weekly schedule allows her one day's respite from her arduous training program. Wednesday, after school, she is free to do whatever she likes.

"Well, I have a lot of pen pals I've made from all the meets I've been at and I like to write to them," she said. "I don't watch much TV, but I like horror movies a lot . . . I don't know, I just like being around the house. I like being with my family."

She's competed in four national meets this year - the Junior Elite Trials in St. Louis, the Mardi Gras Invitational at Louisiana State University (where she defeated two members of the 1976 Olympic team), a Doral Open Gymnastic Invitational in Florida and, most recently, the America's Cup in Madison Square Garden.

"It's fun. Plus it helps with my geography," she laughed. "Sometimes you get a little tired but you get used to it."

Most important, she is getting used to the pressure of performances.

"I think about my tricks before I go on but I don't really listen to anything or say anything," she said. "My first event is the balance beam and it usually wiggles because I'm shaking. But when you're scared it makes you better. And after a while you're not even scared at all."

Frank Bare, executive director of the Gymnastics Federation and mentor of the Junior Elite program, was "very impressed with her skill level," in her tryout for the Junior Elites.

"She may need some improvement in her dance routines and general movement but I think that should come with time. Her stunts are her strong, point as far as I could tell - they're exceptional."

But Bare does add a word of caution.

"There are so many variables in gymnastics," he says. "Injury is an inherent danger in the sport. And if she starts to grow all of a sudden, it could be all over."

That growth factor is so important that a prerequisite for applying to the Junior Elites was that each girl furnish information on the height and weight of her parents and grandparents.

"But if growing too big doesn't become a problem," continued Bare, "it comes down to how much of yourself you are willing to invest in the sport. There are a number of girls around the country close to Stephanie's talent. It's not necessarily going to be a shoo-in for her to make the Olympic team, but I sense that Stephanie wants this thing very much and with her talent, motivation, coaching and young age she has a very solid shot."