I've been dating this guy for about

I've been dating this guy for about 2 years now no off and on just straight 2 years it will be 3 years in November but anyways he wants to have a baby in the future! He said him and his mom had guest over and they got to hold a baby and his mom told him she wants a grandchildren and when he was holding the baby he wanted a kid too with me! When he told me this I was happy and shocked. This meant that he wanted to be with me for along time and have a kid also he asked me if we were to have a kid he wanted to marry me because he wanted a family with me and only me and a kid(s). We talked about this for like 3 hours and I just kept avoiding the question. I would like a family with him but I'm 16 and he just turned 18 in June and I always thought of a family but I'm really focusing on a future career and I never wanted a kid but possibly having a family with him in the future makes me want to have a family with him! The only reason why I just don't want to have a family in a year or 2 is because I'm actually focusing on a test to get me out of highschool early so I can start college and get to starting a really great career of being a doctor but I don't think a family in the making of a career is the best idea? What do you guys think? Do you think maybe after school and everything a child is best? I don't really want kids at all but I might change my mind in the future?