I'm 20 and I've never been in a relationship. Even though I go out a normal amount, I guess I don't make enough of an effort to meet new people or get to know people better after I've met them once or twice.
Before I came to uni I didn't really have any female friends. I was more acquaintances with girls at school. I socialised with them but was never particularly close to any of them. Now I'm at uni I've got a few female friends, but that doesn't seem to make any difference to my luck with women.