OP, I sense your excitement.
Him asking is important to you. It’s not important to everyone on this thread. That’s fine.
So now you have to wait and be patient. It’s good to have had the conversation so you’re both clear on what you want and where you stand with each other. It’s that lack of clarity that’s really hard for lots of people.
Personally, I don’t see ‘engaged’ as a status in itself, but ‘engaged to be married’ is, which involves a plan to marry, usually with some kind of timeframe, even if a bit loose.
So, assuming you take engaged to actually mean a plan to get married, I’d say you have both agreed that’s your plan. He wants an occasion where that is marked…wants to do what he considers romantic. That’s fine…some people want that and others don’t. So for him, doing that is important and until it happens he won’t consider you’re engaged. And you’ve accepted and gone along with that. All good.
I think that the phrase people used to use that ‘you have an understanding’ is exactly wheee you are. There hasn’t been a formal event and announcement, but you both intend to get married. And that’s certainly a step forward and actually really the thing that matters more than a formal engagement. So congratulations on your understanding and the fact that conversation which you initiated has helped to confirm it and settle your mind. You can look to the future knowing the marriage you hoped for is very much on the cards.