So me and this guy I've been seeing for a while started to have sex and it's great but when he's about to finish he pulls out last minute or doesn't at all and finishes inside of me. He didn't ask and after asked if I was on birth control. I told him I don't want him to finish inside of me (very paranoid of getting pregnant at 18). He doesn't seem to listen. I don't know what to do.

UPDATE: yes I'm on birth control but I've seen those rare cases when woman still get pregnant