As soprano Irene Gubrud recalls it, she was an almost disgustingly normal young woman growing up in Canby, Minn.--normal that is, untilthe accident, at 13, that at first threatened and then changed her life.

It happened one evening at a county fair as she was swirling on a ride called the "Bullet." All at once her safety belt snapped. She was slung through the door because there was no safety catch on it, and was thrown 60 feet through the air. There were two injuries, one, a skull fracture from which she recovered in about a month, and the other, a fractured vertebra and damaged spinal cord, from which she will apparently never recover.

At the time, her greatest concern was that the injuries would abort her ambitions as a diver and a cheerleader. But now, 20 years later, there is a larger concern--how does she pursue her developing career as a recital and opera singer when she must walk on crutches?

Indeed, her progress has been slower than some, but last year she had a real taste of celebrity as she won the much-valued Naumburg Competition, which led, in turn, to her Lincoln Center debut and to an appearance on "That's Incredible" concerning her battle with her physical disability, as well as two articles about her in People magazine.

Wednesday she makes her Kennedy Center debut, at 7:30 in the Terrace Theater, replacing the Metropolitan Opera's Barbara Hendricks.

It was 10 years ago that Gubrud was rebuffed by the Met. She was not long out of St. Olaf's College in Northfield, Minn., and she entered the Met's annual auditions. "After the audition they said, 'Well, you sing very well and we will get back to you,' " she recalled in a recent interview. "Then several days later they called me and said, 'We think you are very talented, but we must disqualify you because of your crutches. You could not appear on stage.' But they did offer a scholarship and a chance to tour giving recitals.

"It was a terrible disappointment. But it forced me to face up to reality. I decided I had two alternatives--either have enough therapy that I could get around a stage, or become just a concert artist."

Finally she went to a therapist who had devised a program of exercise and meditation. After three years, she was "walking" with a therapist on each arm when they suddenly withdrew and she took three steps and then fell. On each try the number of steps increased, until one day she could walk limited distances without crutches for the first time in 18 years. After many tries she taped her ankles one day and walked to center stage while appearing with the Minnesota Orchestra under the late Andre Kostelanetz.

Meanwhile, her career as a concert artist continued. In 1977 she appeared with the New York Philharmonic and Pierre Boulez in the world premiere of George Crumb's "Star Child," a work she commissioned through the Ford Foundation.

It was only last fall that she made it to the opera stage for the first time, in a production of Puccini's "La Bohe me" designed for her at Opera St. Paul. She sang Mimi. "I could use my crutches until I got ready to go on stage. Then I only had to walk eight steps to get where I was going," she recalled. "During the scene where Rodolfo and I were looking for the key I was seated on the floor, and I could walk off stage on his arm. I used one crutch under a long, floor-length cape in Act Three and I was carried on in the last act, which made sense because Mimi is dying."

Among the other roles she thinks she can manage on stage are Tatiana in Tchaikovsky's "Eugene Onegin," the Countess in Mozart's "Marriage of Figaro," Desdemona in Verdi's "Otello" and Melisande in Debussy's "Pelleas and Melisande." All these roles fall within the normal range of her voice, which she described as "a lyric voice toward the bigger side."

She admitted that her pride has sometimes made her self-conscious about appearing on the concert stage with crutches. "There's nothing wrong with putting something on the stage that I can lean on after I get there, but I fought it for so long," she asserted. "Now, normally I am seated. I finally had to say to myself, 'Look, sweetheart, this is the way it is.' "

Another worry, she said, is that she might be publicized more because of her disability than because of her singing. "I don't want to use that as a gimmick," she said. "But I feel that these things can help to break down negative attitudes about the handicapped."

Where does she expect to be in 15 years? "I will still be singing," Gubrud said. "And I will be singing with all the major operas. I would say 40 percent of my singing will be in opera."