boyfriend and marriage

I've been with my boyfriend for 2 1/2 years and we're both 20. We're no where near to wanting to be engaged or married, but I like the idea of knowing it will happen after we both graduate college. I really liked the idea of a promis ring, but when I mentioned to my bf he got offended in a way & told me that he does not need a ring to prove how much he loves me. I agreed & got over it. Next year he's planning on transferring bc of football & I got upset when I heard the places where he's planning on going, as they're far & idk what that would mean for us. He told me straight up "just come with me babe." This took me back. The other day I joked with him saying my last name won't be my last name forever, & he agreed & corrected himself to his nickname as my last name. I joked and asked "so when are you gonna make it happen?" & he told me he doesn't know he's not planning that right now. We've talked about the future & when getting married & having babies is the right time. I know he really does believe we have a future together, because he's talked about it with me, but I'm just scared in a way ???