If boys have liked me, then why can't I get a boyfriend?

ok well, I am 16 and never had a boyfriend. there have been many guys that have liked me, and have thought I was pretty. I am not being conceited I am just trying to explain my situation. however these guys that liked me weren't the right ones for me and I wasn't interested in a relationship with them. but if guys have liked me and think I am pretty then why can't I get a boyfriend? I'm just so tired of seeing everyone else being in relationships and it feels as if I will never have one any time soon. unlike some other girls I do have standards though, I won't go out with just anyone. I want a sweet guy with a good personality. I do definatley want someone I am attracted too though. I am not desperate and I will not just go out with any guy. what's the problem then?