Don't even *think* about dresses until you've had a proposal, secured a date and decided on the type of wedding you both want.
Imagine getting all excited over one style of dress only to find that it's not suitable for the type of wedding you end up agreeing to have. Even worse, imagine getting excited over a dress and having him not propose at all.
I think it's really worth tackling this in the correct order.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.