Should I come out?

I want to come out to the people at my school and I'm not really too afraid about that. I'm more concerned about my family. I think my sisters will come around to it pretty quick but I know my mom will be a much tougher battle. She definitely believes homosexuality is a sin but I've seen her be very tolerant and I believe she will learn to accept me in her own time. The process of that seems very messy and frightening, though. I kinda want to get it out of the way before I go off to college. What should I do?