Mr Shaqy - your goal to dunk is good.... but, I want you to think about this.... watch some high school games and tell me how many dunks you see compared to a really good shooter especially from the arc. You have 3 more years of Middle School and there is lot more of your game to work on than just dunks.... good defense, good inside game at your height.... ball handling, passing and mid range shots..... 3s if you can do that.

Add some flair with a double-pump. Suggesting you're so high you could dunk it twice, in the double-pump dunk you bring the ball back down to chest level at the apex of your leap, then force it back up to slam it with authority. Some notable players, Tracy McGrady among them, would do this regularly while spinning in the air, doing a 360 dunk variation.
Nothing generates more excitement in a basketball game than watching the creativity and athleticism of a player flying through the air and finishing with a slam dunk. It can single-handedly change the dynamic of the game and turn a regular player into a star. Although it helps to be tall or have a natural leaping ability, short people can develop the skills required to perform this amazing athletic feat with proper training and technique.
The simplest method to measure an athlete's vertical jump is to get the athlete to reach up against a flat wall, with a flat surface under his/her feet (such as a gym floor or concrete) and record the highest point he/she can reach flat-footed (the height of this point from the ground is referred to as "standing reach"); fingertips powdered with chalk can facilitate the determination of points touched on the wall. The athlete then makes an effort to jump up with the goal of touching the highest point on the wall that he or she can reach; the athlete can perform these jumps as many times as needed. The height of the highest point the athlete touches is recorded. The difference between this height and the standing reach is the athlete's vertical jump.