Andrea Jaeger is 17. And at the moment, it's a little hard to look at her in historical perspective. But Jaeger is more than just the third-ranked player in the world, more than just the tour's youngest millionaire. She is a sociological phenomenon. She loves being a girl who does the things that boys always did and doing them better. She loves being herself.

The words tumble out in an irrepressible stream of consciousness. "My sister Susy, she was the other half," Jaeger said. "When we were expected to wear skirts, she did. She was proper. I was always getting dirty. I think they thought it was something I was just going through."

Jaeger, who plays Peanut Louie in the Virginia Slims of Washington quarterfinals at 5 p.m. today, is about what women in sports are going through. "She wouldn't have existed before 1970," said Ana Leaird, Virginia Slims' director of worldwide operations. "Chris (Evert Lloyd) became a role model for a certain generation that liked ponytails, earrings and makeup. Andrea became a role model for kids who want to be able to play soccer and watch football and know all the stats about the best pass defense. Before they had to keep it all within. Now they can afford to have male attitudes about sports and be female and be feminine. Andrea helped make it acceptable for women to have a male attitude about sports."

At the U.S. Open last fall, she gave seminars on playing hurt, something she did quite a bit in 1982. She sounded almost macho, telling how she asked for an injection once but no one would give it to her. "When I grew up, if something hurt, I just played anyway," she said. "I've been hurt more than I said. It's not like every time I get a hangnail I call UPI."

Football still beckons, although she has given up her motorcycle. "After a certain age, girls don't look good on motorcycles, unless you're on the back and a guy's driving," she said. "That's cool."

She got her ears pierced last week and has started wearing jewelry. When the Lloyds gave her a bracelet in Australia, she insisted upon wearing it on the court even though it was too big. "It's not like I'm going to go out and wear a dress and stockings to practice," she said. "Some things never change on the inside."

When you grow up in public, as Jaeger, Evert, and Austin have, all changes are duly noted. Jaeger is not quite a woman, no longer a little girl. "In between, aren't I?" she said.

Sometimes that makes things awkward for her on the tour. Those her age are not as accomplished as she; those who are as accomplished are not her age. For a long time, she spent most of the time on the road with her father and coach, Roland. But, that, too is changing. She is more independent. She traveled to Australia and Japan without him. "She's more on her own," said Martina Navratilova. "She seems happier. When she first came on the circuit, she was easygoing."

She was the heir apparent to the little darling throne. Then tennis became serious, a job. "I figured, I don't have to enjoy this, I just have to play well," she said. "I was afraid to go and do other things because I was afraid it would affect my tennis. Now I think it might help."

People around the tour say she may be petulant one moment, the way 17-year-olds can be, and thoughtful the next, the way few players are. This week, she hid a present for tour referee Lee Jackson under a pile of papers on press row. Last week, she tracked down Regina Marsikova by telephone in Czechoslovakia after her passport had been revoked. Last fall, before the Open, she bought $100 worth of toys for a new hospital in New Jersey.

Her injuries changed things, too. "You learn to respect other things than tennis," she said.

In the last 18 months, she has played with a pulled groin muscle, a stress fracture in her pelvis and tendinitis in both feet. Older players question whether injuries to Jaeger and Austin are due to overuse. "I didn't know what the word injury meant until I was 20 years old," Navratilova said. "These kids practice two and three times before a match. If I did that, I'd be as flat as a Perrier that was open for two weeks."

Roland Jaeger said, "They played just as much in their time. They just had easier matches . . . When they came in, they weren't pushed as much. They don't realize today to get in, it takes much more. So definitely, injuries come in."

Nowadays, he says, talented children "are pushed by their own destination."

"I'm harder on myself than my Dad has been," his daughter says. "People don't realize it. Lately, he's been telling me to settle down."

She never said she was going to be No. 1. She never said she was going to be No. 3, either, which is "a protective thing for me," she says.

Already, she is "a better all-court player than Evert or Austin," Navratilova said.

"Cocky" is a word that has been used to describe her.

"Am I cocky?" she asked Leaird.

"On the court, you are," Leaird replied.

For just a moment, she hung her head among her blond curls (another change, no pigtails). "I don't do it on purpose," she said. "It's just my nature. When I played soccer (as a sweeper), if they scored, it was my fault, not because they made a good shot. That's why I'm at where I am."

A pause. "Cocky is different from stuck up."