Re: 100 enough?
Please, read again recent threads about the same topic. there are things already written there that will be useful for you.
However, I'll repeat the most important things:
_DO NOT USE OVERWEIGHTS, until your connettive tissue has finished its developement and growth. If you stress too much tendons and ligamens, while you'll be able to see a satisfying growth in mass and power of your muscles, you'll put yourself in danger of serious complications and injuries for ankle, knee, hip and lower back.. You should really wait until you're 18 before using overweights.
LEARN THE KNOW HOW. Your body will have plenty of time to develop, your technique will be harder and harder to train as years pass by. Take care to learn how to jump now, and then become stronger.
NOT ONLY CALF: Calf is only one of the many muscles involved in a complex gesture such as jumping is. You must take notice that feet muscles, calves, the shinbone muscle, the quadriceps, all other muscles inside the thigh, abs, back muscles, and arms are cooperating to reach up to the basket. Thinking only about your calves will only make you deformed.
Again, the simples suggestion. Learn how to jump. Moreover, learn how to run. Vertical reach depends much on the horizontal speed you're able to change into vertical speed. If you are slow, you won't jump high. However, learn how to run and jump, and if you want to train your strenght, train it completely: sprinting uphill, several forms of jumps while rising the stairs and rope jumping are good total body exercises.