I don't know anything about dating and remarrying after a divorce, but from what you've said, I think it'd be a good idea to give the relationship with your GF about a year of so before tying the knot. Regardless of the cause of your GF's cold feet, if everything is good between the two of you, then waiting shouldn't hurt. Get to know her friends and family, have some fun and revisit the proposal later.
Again, I don't know anything, so get other viewpoints; certainly don't act on my advice.
