I (22f) know my boyfriend (22m) is right but I can't get on board. Is it even possible?

I'll make this short since I'm on mobile. But I can elaborate in comments.

Bf and I have been together 4 years. I got into grad school in the same city where he's starting his post college job so we decided to move in together. That starts in August.

I really want to get engaged. We've talked about it a lot but he says he's not ready yet. We're young and his reasons do make sense. But I'm just so uncomfortable living with someone without even an engagement, let alone marriage. I came from a traditional home and this is unheard of.

I keep hoping a proposal will come at the end of every date, and it ruins the dates sometimes. Bf says that he thought we agreed to wait, and while we did, my hearts not in it. How do I get my heart in it?

Tl;Dr: my bf isn't ready for engagement and I am.