I like an older guy. What do you think?

He's my sister's roommate and he's 21 or 22. I just turned 18. He's really nice and really hot. He kind of hit on me but i can't tell if he's just kind of a man ho so to speak lol. What do you think? P.S. I'm a virgin but I know he has like one night stands. Is it worth getting involved if there's a chance it may not work because he might need ? Because I'm not ready and I would love to be able to save myself from a heartache. Also, I've only hung out with him a couple times...how would i even get to know him well enough? We've talked on facebook but not much.