That’s a lot of pressure to put on yourself, especially since you can’t go back in time. Why think about making up the “lost” time when you have years of time ahead of you, which I think amounts to a lot more than the time that’s behind you. Don’t stress out about this, because you can’t change this past rejection and that’s OK, it’s brought you both to a good point.

Also, I expect that you needed to be in a different mental space to value him to the extent that you do now. If you ended up doing anything earlier, you may not have had the perspective needed to stick with a relationship like this. It takes time to come to this sort of realization, and being upset you took that time doesn’t strike me as a response that’s fair to yourself.

You guys are getting married, that should be proof enough that you value each other. If he’s focused on a past when you rejected him, you have accepted him fully now and in the future. If you are focused on a past when you rejected him, again, you accepted him fully now and in the future. You shouldn’t beat yourself up for needing time, as again, if you got together earlier, it might have been a failed relationship with potential that you’d be regret here.