Age difference, Future and Sex?[[pleaseee help!!]]?

OK,, so me and my bf have been dating for about 4 months and we've known each other for about 2 years.. We r happy and i love him very much, and he loves me to, i mean we r both really seriously in-love... but we have a slight age difference you see i'm 14 and he's 17. I just cant help wondering.. he's in the middle of his second last year of high school and then he's off to college while i'll still be stuck in school... and i'm just worried when he goes off to college does he really still want a gf in high school?? Though we are planning to go to the same college. Then the other thing is sex. it is normal for me to at least think about it. i do not want to hear comments telling me i'm to young to think about these things..well as i said i'm 14 almost 15 now and i do not want to have sex right now. neither does my bf. We are both Christians. But we are considering it to have sex when i graduate high school...good idea or bad? i do want to though. Just give me some advice.. these things have been seriously bothering me lately ase me and my bf are getting more serious. Also my bf is very loving and respectful*