Any hope for the future?

Hello, so, yes i am young. I'm fixing to turn 18. I've been in a serious realtionship for a lil while now and i'm certain he's the one i know i want my life with. Yes, i did mention i am young and most people would say i don't know what i want. Moral of this is we don't use anything. He doesn't pull out or any of that and its been like that for 10 months so i don't see how i've not gotten pregnant. I'm worried that maybe later i will have problems. All i want is to be a mother one day. I've thought about going to see a doctor soon just to check up but something tells me usually when a doctor says you can't have kids they're wrong. And whenever it happens, it happens. I'm just scared. A reading that i might have alittle hope later on of course?