Rotating Core and Shoulders as fast as you can

Is it safe for a 15 year old to rotate his Body as Fast as he can or could I hurt Myself in the process of putting that much force into a pitch??? NEED TO KNOW I PITCH TOMORROW.

Your brain is smart (shocking eh? haha). It will only allow you to speed your body up to the point it knows it can decelerate it.

That is why over/under training is so effective.