A couple quick and easy engagement ideas. One idea is to make an ornament for your christmas tree with your engagement ring in it. When you’re finished opening gifts, tell there’s one more gift left. Either let her find or take it off the tree yourself.
A second idea is to place the ring box inside several different size boxes. She’ll think she’s opening up a large item, but she’ll keep opening successively smaller boxes until she gets to the one box that matters. Be ready with your engagement at just the right moment.
Have fun with it and hope ends well.