We were in the same situation as you and I really wanted to go to Disney.
The difference is we are expecting twins and it is a higher risk type preganancy.
I asked the Dr for her adivce and she recommended us to go however I just didn't feel right about it because being from Canada, the insurance situation if the babies are born is very different.
If this was not a twin pregnancy and all was good and I had my Dr's approval, I definately would go!!
Just take it at an easy pace, drink tons of water and most of all, have fun!!