If you really love Disney and it's affordable, go as early and as often as you want!
From someone who spent 4 years on the black infertility rollercoaster, and then adopted... I say, GO and ENJOY every second, lol.
A great picutre of you and your newborn baby standing next to Pooh or Cinderella to hang in his or her new nursery maybe worth the trip alone, and when someone asks you why you would take a baby, tell them you deserve to have some wonderful memories too.
Plus, when your children are older and they drag out the photo albums, they'll get a kick out of seeing how little they were at Disney, and what an incredible feeling it will be for them when they see happy and excited you were to be new parents....that you couldn't wait to take them to Disney!
Ok, I'm a sap, lol, but if you go when it's cool and not crowded, it will be magical.