Age difference :((

So atm I am a sophomore and I'm 15 and I've been talking to a dude that's 17 and is a senior. He is a very sweet dude and we've been talking for like 2 1/2 months and our bond is just getting stronger and stronger and he makes me extremely happy. Both Mine and his family know that we are talking + our friends. But the problem is he is turning 18 in march and I'm Turning 16 in May. Is that a problem if we are talking beforehand him being illegal for me or would it still be considered illegal? Please Dont leave rude comments, I really like him and he really likes me.