Having dreams of playing college athletics is an admirable one, but if there is no plan of action attached, it only remains as a dream and not a goal you're striving toward.
So you've decided playing a sport in college is a major goal of yours.
Congratulations! Having the desire to accomplish a goal like this has to start somewhere, and setting such a goal is the first step.
Every student-athlete has different reasons as to why they'd like to play a varsity sport in college. There are no right or wrong answers to that question, as long as you're being honest with yourself.