How can I jump higher? Are high leapers born or made? Is it too late for me to become a pretty good player now that I'm 23? Am I starting training too late?

Hi Deangelo,
Pliometrics are one of the best excercises for increasing your vertical jump. Here is a good page with a brief explanation and a few good exercises:

Plyometrics FAQ

Hope this helps. Take care. :)

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You are NOT too late. Try weight training (like squats or calf raises) or try plyometric exercises. Probably a combonation of both would be best. You don't need natural talent to increase your vert, but work hard and stretch a lot and you will be on your way.