Instead of punching a time card these days, Jenifer White, the favorite to win the women's division in Sunday's Perrier Cherry Blossom 10-mile race, is punching a stop watch.

In December, White gave up her job as a nurse to devote full time to running. "I could work if the job had the right hours," said White, 26, who bears a strong resemblence to actress Mia Farrow. "But at the job I had, it was hard to take off on Thursday and Friday, so I could travel to races. So I quit . . . I had to do it."

Sitting in a rocking chair in the second-floor dormitory apartment she and her husband, Max, occupy at the Episcopal School in Alexandria, White talked about how she took up running almost seven years ago.

"My neighbor invited me to ride my bike along with him while he ran 13 miles," said White, who weighs 107 pounds. "It was no problem for him, but I had to work to keep up." She weighed 125 at the time and she knew it was time to hit the road and get in shape.

"I was inspired, so I got a pair of running shoes and I never lost that inspiration," she said. Since then, her inspiration has led her to victories in races at distances from a mile to 10 miles.

In 1978, she qualified for a U.S. international cross-country team and traveled to Limerick, Ireland, where the team won a gold medal.

White won the Cherry Blossom race in 1978 and placed fifth in the national cross-country championships that year.

At the CYO indoor track meet at Maryland in January, she ran her fastest mile, 4:41, finishing fourth. This winter, at the Track Athletic Congress national indoor championships in New York, she finished fourth in the two-mile in 10:03.7.

Although she prefers track events over road races, White recently won the women's division in the prestigious Jacksonville 15-kilometer River Run and the Lady Equitable 10,000 meters in Baltimore last week.

"If they took all the top women from 10 kilometers to 10 miles, she would be in the top 10, may be top five," says Bruce Robinson of Silver Spring, a top marathoner and one of the directors of the Cherry Blossom race.

"On the track, for example, she's not in the same class as a Mary Decker. But on the road, she's excellent and she's getting better because she works so hard. The thing is, she's so quiet and low-key, hardly anybody knows who she is."

Since she's been winning, invitations to other races have been coming in nearly every day. Her trips to the various cities are financed by the Nike Shoe company (they have provided her at least three dozen pairs, in every conceivable color) or by the event extending the invitation.

White's main goal will be the TAC national championships in mid-June in California, to be followed two weeks later by the Olympic trials in Eugene, Oregon.

She'd like to make the U.S. team, but more important, she'd like to prove a point to the International Olympic Committee. On the last day of the trials, there will be an exhibition race of 5,000 meters so that the women can demonstrate that they can run distances longer than 1,500 meters, the longest Olympic event for women.

"That's what I'm pointing for," White said. "There probably won't be an Olympics, but I want to keep on competing forever. I love it."

White met her husband, Max, a math teacher who is an ultramarathoner and who also is entered in today's race, while she was out running cross country.Both were students at the University of Virginia at the time and, "We kind of hit it off right away," she said.

"He told me I could be a really great runner," she said. "So for the next year, White worked hard, and ended up qualifying for the Boston Marathon in 1974, finishing in the top 12 in the women's division.

Now she runs six to 20 miles every day, sometimes with her husband. "It helps to go with him," she said. "The only way to improve is to push yourself."

Max went slow for her at first, but now, he says, "I want a shirt that says, 'Mr. Jenifer White'."

"For most people it might be a problem" said White. "But he's been very supportive and just as excited as I've been when I win."