AIO my (F17) boyfriend (M20) asked me to marry him secretly

Me and my boyfriend have been dating for about two years now. For the past five or six months I’ve been living with him because of a family situation and having no where else to go. He’s a good guy, pays for nearly everything and is a sweetheart. However we do have our own sets of issues, he tends to be far too touchy and obsessive. Recently he brought up the idea and asked me to get a marriage license. I immediately said “no, I’m 17 I’m not ready”. He went quiet after that and dropped it.

A few days later it was just eating at me so I decided to ask him to elaborate but that my answer hasn’t changed. He said “I don’t know if there’s any other way for us to have a joint account…” and in relation to me going to college soon: “I don’t know if I can take that debt if we aren’t married”. (Mind you, I’ve never asked him to) He said we could get married legally and have a ceremony later down the line. When I asked him if that’s what he really wants he said “yeah, as soon as possible”. And that we could have my mom consent for me. I still disagreed and held my position, but am freaked out, am I overreacting? What should I do?