Softball: How to stop overthrowing?

I think that it's funny that I overthrow alot (not in a game just when I practice in my yard: I throw to a tree) since I'm only 4"11 and I just can't imagine the thought of me throwing the softhall over someone who is 5"7's head. I want to be an infielder but I fear that my overthrowing might land me in an outfield position. Am I throwing too hard? Am I not bending my elbow enough or something?