Seventeen-year-old Joy Keo lay crumpled on a bedroom floor, struggling to breathe, for almost two hours last August after her former boyfriend fired four bullets into her body. The first shot severed her spinal cord and left her paralyzed from the neck down. Her mother says doctors feared she would not live.

Last night, against what seemed like all odds, Joy Keo donned a white cap and gown and received her diploma as a member of the J.E.B. Stuart High School Class of '83.

"I think to myself, if I kept myself alive when everybody else had no faith in my living, then I can overcome anything," Keo said, as she sat in her wheelchair in her family's Lake Barcroft living room yesterday afternoon.

But Keo said she still has not overcome her fear of her former boyfriend, 20-year-old Chuck Brewer, who was sentenced in March to serve 50 years in prison for shooting her in a jealous rage after she broke off their romance.

"He's eligible for parole in nine years and three months," Keo said. But for the most part, she added, "I sort of put him out of my mind."

Keo returned to her high school classes in early April after more than seven months in hospitals and rehabilitation centers.

With the help of friends and after-school tutors, she kept pace with the class she had left in August and maintained the honor roll grades she had earned before what she calls "the injury."

At last night's graduation ceremonies, her name headed the class list, just after the valedictorian and salutatorian and the class officers.

As her sister, Mali, 16, pushed Joy Keo's wheelchair up a ramp to the stage in the center of the school football field, the senior class rose to its feet in an emotional outburst of cheering for the student who had overcome the greatest obstacles to earn the coveted diploma.

Keo, a quadriplegic with only limited use of one arm, sat in the front row of the sea of white robes and caps throughout the ceremony, listening to the lengthy graduation speeches on determination and courage and success and the future.

Many of them echoed the sort of speeches that Keo has given herself in her efforts to overcome the barriers between her handicap and the diploma.

It was the nonacademic side of high school life, she said, that caused the most emotional pain. "I went back to school just when all the spring sports were beginning," she said wistfully. "All my friends were dressed out to go play soccer or be cheerleading--the things I'd be doing. That was real hard."

"She's only beginning to realize what her limitations are," said her mother, Marion Keo. "When she was with the other handicapped people at the Woodrow Wilson Rehabilitation Center in Fishersville, Va. she didn't realize what she couldn't do."

Joy Keo says her most persistent frustration is her dependency on friends and her family for virtually every daily routine, a dependency she said she thinks sometimes borders on being an "imposition."

A hired attendant arrived at the Keo family home each day at 6 a.m. to begin the three-hour effort to get Keo ready for school--bathing her, dressing her, applying makeup, and putting her on the special school bus for the handicapped that picked her up each day.

"We don't think of her as being sick anymore, but a lot of her spirit has been taken. She's learned a lot of patience," Marion Keo said.

Sitting in her wheelchair, clad in a fashionable blue-and-white striped dress with wide red belt and red stockings and white pumps, Joy Keo talks about her immediate future as though she is just another typical member of the Class of '83.

She has enrolled in a writing program at George Mason University where she plans to start classes in the fall with the aid of two scholarships.

If she can persuade college officials to extend the scholarships to cover room and board, she plans to live on campus in a dormitory room that her mother already has selected for its wide doors and wheelchair accessibility.

After months of physical therapy, which Keo describes as "physical torture," she can feed herself with the partial use of one arm, turn book pages and type with a custom-made $124 mouth stick, and with extreme effort move her legs a fraction of an inch.

Her favorite pastime is shopping for clothes. She bought a white evening gown and wore it to the senior class prom last week.

Keo said she plans to spend the summer using the electric typewriter she received as a graduation gift from her family to begin writing a novel about her experiences--the stormy relationship with her boyfriend, the shooting and her struggle to cope with life as a quadriplegic.

Keo hesitates to discuss long-range plans about her future or the possibility of being able to walk again, which doctors say is virtually impossible. But there is a hint of the determination that has brought her this far.

"I've always been strong-willed. It's part of my personality. I'm stubborn," she said. "If I set my mind to something I can get it done. Before this, I never really had any challenge."