It is a perfect race to start with! It was my first half and I would highly recommend it. The thing about this race as compared with others is that it is walker friendly so this isn't one you have to run the entire time unless you want to. I would recommend the Hal Higdon Half Marathon training plans. He has them for walkers, and for runners of all different levels.
Oh, and as far as shoes, make sure you go to a running specialty store to get your running evaluated. That way, you get the best shoes that work with you. The right shoes make a big difference!
I was intimidated too - but Disney is so much fun that the last thing you need to be is intimidated! You have plenty of time to prepare!!