Scared of Roommate's Reaction

I'm going off to college in August and I am terrified to how my roommate will react to me being gay. He doesn't know I'm gay already, and I don't know if he is homophobic or not. How do I tell him? Will he be pissed because I didn't let him know before or if he is a homophobe? All I know about him is that he is from Virginia and born in Indiana and that he's 18. Can someone help me because it's really stressing me out?