Is it normal to be 17 and a virgin?

i'll be 18 this fall and i still haven't had sex, and I'v never really had a boyfriend either. Your probably thinking its cause I'm ugly or some sort of outcast, but I'm really not. I'm not some STUNNINGLY BEAUTIFUL girl but i think im defiantly pretty. Boys flirt and hit on me all the time at school and i have a good group of friends but im the only virgin :-/