CLEVELAND - Kevin Garnett is all grown up, already. He is 20 years old and betrays neither innocence nor inexperience. He stands 7 feet from sole to scalp, but shows none of the gawkiness common to young giants.
He jumped straight from high school to professional basketball and has landed as softly as a snowflake. The Minnesota Timberwolves' manchild is a kid only so far as the calendar is concerned.
''Kevin Garnett has come a long way,'' Michael Jordan said Saturday, ''and you know what's so scary about it? He's still got a long ways to come.''
The National Basketball Association doubles as a day care center these days. The teams are increasingly populated by petulant children, overgrown adolescents whose growth can not be confused with their maturity.
Allen Iverson is the glaring example. Kevin Garnett is the contradiction. Less than two years removed from Chicago's Farragut Academy, Garnett is both an All-Star and an ambassador, the most personable of the NBA's prodigies. Tonight, he will become the second youngest player ever to participate in an NBA All-Star Game (behind Magic Johnson), a status nearly as exalted as being Little Penny's ''Main man.''
''He is one of the good things about today's NBA,'' said Timberwolves General Manager Kevin McHale. ''He has respect for the game, respect for himself and he loves to compete. What isn't there to like about that?''
Answer: Not much. Spend an hour in Garnett's company and you come away convinced that he defies pigeonholes of any dimension. He has spent his young life having people fawn over him and has managed to retain his humility. He gained great wealth as a teen-ager, and it cost him neither his ambition nor his drive. He skipped college without suffering the harmful side-effects which typically befall the young and the restless.
''I never looked at anybody else and said I can be like them,'' Garnett said. ''What you have to understood is that everybody's different. I never wanted to be the next guy. I always want to be the first of something. I knew once my opportunity came I was going to take it and run with it.''
The only way Kevin Garnett could have missed was through self-destruction. He had the size to play center and backcourt ball skills. He has become the NBA's tallest small forward, a player prototype as revolutionary as were 6-9 point guards before Magic Johnson.
Garnett has averaged 16.4 points, 8.1 rebounds and 2.5 blocked shots per game in his second season with the Timberwolves. Each of these figures represents a significant improvement on his rookie season. Still, Jordan says, ''You're just seeing a touch of his skills.''
''I think this is the beginning of a good thing,'' Garnett said. ''I have a lot to accomplish in my life and I'm definitely not going to stop here. I'm at the bottom of the mountain trying to get to the top of Mount Kilimanjaro.''
He is, to be sure, nearer the summit than the base, but Kevin Garnett chooses to court greatness when he might be satisfied with an elite status quo. He listens. He learns. He lives by the credo, ''Never get burned twice.''
''He can shoot the ball and handle the ball, but the thing I love about him is that he is a little bit of a throwback,'' said Detroit coach Doug Collins. ''He respects what this game is about and he really loves to play. I admire that.''
Collins remembers interviewing Garnett before the NBA draft and being ''mesmerized'' by the maturity of a high school senior. Detroit had the eighth pick, but Garnett was gone at No. 5. From a distance, it seemed a huge risk to take a high school player that high. Those who had met Kevin Garnett, however, had fewer misgivings.
''I never set my sights and my thoughts on what people say about me,'' Garnett said. ''They don't know me personally. I never sweat what anybody says about me. I'm always out to prove somebody wrong. No matter what people tell you, you can always reach your goals. If you keep your mind straight and your head straight and you listen and you learn, anything's possible.''
If a guy is good enough and wants to get better, his age is arbitrary. So it is with Garnett.
''That guy is more mature than I am,'' Kevin McHale said. ''And I've got five kids.''