Should I give up or go hard?

Okay, well I play ball and everyone tells me I have the potential to play college ball. Im 15 years old and a freshman btw. I go to a big school in GA, I'm talking bout more than half the team has committed to a Division 1 school. Anyways I got cut from the freshman team and I really do not know why, and I was too afraid too ask. I have been real bummed about it and haven't played basketball in more than a month. What should I do start practicing for AAU or give up =/?.....And is three years enough to get noticed for college?