Worried

I have unprotected with my boyfriend and have for quite sometime, and I am on top of my tracker, so it's pretty in sync with my body. I've had sex before my period, after, before ovulating, during and after. I'm kind of worried that it is physically impossible for me to get pregnant. I was born 3 months early and I'm starting to think that has something do to with it... I don't really want to go to the doctor because I'm scared to find out that I will be unable to have a family of my own.