I don't think I can get pregnant..?

Lisa
So I've been with my boyfriend for about 2 years and we've been having unprotected sex for over a year now. We visit the doctors once every few months and we're definitely clean! I'm just worried that I might not be able to have children in the future because I haven't gotten pregnant and it worries me. (Not that I'm trying to get pregnant but you know what I mean) He does do the pull out method but that would mean it has worked 100% since we've been having unprotected sex... Do you think I should be worried? I'm 21.