Whoever said "Youth is wasted on the young" never had to reckon with the crop of tennis professionals. With little or no waste, talented juniors are entering the pro ranks earlier and getting rich quicker than ever before.

The worlwide profusion of junior tennis events has turned the top 15-year-old girls and 17-year-old boys into seasoned veterans. Intensively trained, well-coached and match tough, they can hold their own with anybody.

Take Andrea Jaeger, for example. She turned 15 on June 4. But she turned pro in February. Seeing her play, one wonders why she waited till then. Tenacious, with solid ground strokes, she soaked up the teachings of her father, Roland.

Four weeks ago, Andrea suffered an unfortunate first-round loss in the French Open. While it was a big disappointment, she displayed a maturity unusual for most 15-year-old 10th graders.

"This is only my second really big tournament," she said, "so I honestly didn't think I would win here, but I think I could one day."

In her first really big tournament, the 1979 U.S. Open, she drew a much older player -- 16-year-old Tracy Austin.

"I was more nervous in that match than I was today," she said. Does she feel she is Tracy's heir apparent? "No. Tracy is Tracy. I'm Andrea. I need to play more to find out how the other girls play." Even Evonne Goolagong Cawley is a "girl" to Andrea at 15.

Jaeger made more than $40,000 in her first three months as a pro. And she wasn't too surprised at her initial success. After all, she had been the youngest winner ever of the U.S. Girls 18-and-under title. Her first Women's Tennis Association ranking was 19 -- two places better than Austin's first WTA ranking. She is so young, relatively speaking, that an amusing question about marriage in 10 years or so draws a quizzical stare. Talk of a boyfriend elicits a nervous giggle. A quarterfinal berth at Wimbledon is a definite possibility for Jaeger.

Bettina Bunge is another child prodigy. Seventeen years old on June 13, she was born in Adliswick, Switzerland, spent 13 years in Peru and now lives in Coral Gables, Fla. I remember watching her play Virginia Wade on BBC-TV last June from Eastbourne, England.

Seeing her at the players' hotel three days later in London during Wimbledon, I said to her, "You played quite well against Ginny. How do you like the grass (courts)?" I fully expected some meek and modest answer. What I got was, "Well, I beat Sue Barker the day before I played Virginia so I really thought I could win." That fearless attitude carried over to this year, because in Kansas City she beat Billie Jean King, who, at 36, remains a bit fearless herself.

As a resident alien, Bunge is entitled, like Martina Navratilova, to be ranked by the U.S. Tennis Association. Two years ago, she had a No. 2 ranking in the girls 16-and-under right behind Tracy Austin. Last year, her WTA ranking jumped 73 places from 105 to 32. Currently ranked No. 23, a top-10 spot is a virtual certainty one day for Bunge.

If 14 seems to be the cutoff age for girls who turn professional, the boys seem to wait a bit longer. The difference is purely a matter of upper body strength. Whereas the 15-year-old Jaeger is almost as strong from the waist up as 27-year-old Chris Evert Lloyd, a 15-year-old boy is no match for Bjorn Borg.

Scott Davis, though, comes as close as any 18-year-old. This California youngster just overwhelmed the junior ranks last year. At 6-foot-2 and 164 pounds, he physically towered over his opponents.

His 1979 record impressed Tony Travert, U.S. Davis Cup captain, so much that Trabert brought him along with the Davis Cup team for practice. And, as any American junior will tell you, that's akin to being knighted.

I was able to watch him play the special junior event at WCT finals in Dallas this year and the French Open, where he received a wild card. In the players lounge at the French, he told me, "I'd like to get as many ATP points as possible this summer because I'm entering Stanford University this fall. (He is delaying his entry into the pro ranks for now). A high ranking makes it easier for me to play an occasional tournament during the school year. I'm only allowed four wild cards a year.

"My results this summer will give me a pretty good idea of how good I am and whether or not I'll stay at Stanford for four years. I realize the Grand Prix tour is not like playing the juniors but I'm willing to pay my dues and find out."

And find out he will. I have no fears that Scott, the 1979 Open, national, grass court, indoor and hardcourt junior champion, will be a U.S. top-10er in three years.

Only one junior player was viewed as high or higher than Scott Davis last year -- Ramesh Krishnan of India. I've seen him play many times and he can play on any surface. The '79 Wimbledon and French junior champion, Ramesh is the son of a famous father, Ramanthan Krishnan, arguably India's best player ever.

After he beat Scott Davis at the WCT junior event in Dallas last month, he told me, "I'm trying to develop an all-surface game. I played in Australia two winters ago and that helped my grass court game. Vijay (Amritraj) also plays well on grass and we have some quite good grass courts in India.

"But my father was very good on clay and he is encouraging me to play on everything. Scott is going to university in the fall and that might hurt his development. But we don't have such things as tennis scholarships at Indian universities."

Even though Scott Davis will attend Stanford while Ramesh tends to his tennis, he will have his hands full in the tough Pacific-10 conference.

You'll be seeing and hearing quite a bit from Andrea, Bettina, Scott and Ramesh in the '80s. Four years ago this "new wave" of tennis prodigies was forecast as having the potential of keeping up with their more senior colleagues.

But the average age of the top 10 men is currently 25 years 10 months, and the women, 26 years six months -- and dropping. Pretty soon the world 21-and-under rankings may well be the world rankings -- period. Meanwhile, check the tournament results this year. Davis and company could pull some upsets.