Our first child was 6 mos. old on her first Disney trip, and our second child was 4 mos. the first time we took her. Next Oct. we will be taking 3 kids - we will have a 3-mos-old! We travel at slow times, but here is my advice for you....
Go with the mindset that you are NOT going to see everything.
Keep a slow pace and don't try to cram too much into your day.
Take advantage of the baby care centers available at each park. They have feeding facilities and supplies, diaper changing areas...anything you could possibly need.
FASTPASS! Use Fastpass for the most crowded rides and go have a snack, feed the baby or whatever while you wait for your scheduled time to ride.
Babies are pretty resilient. People always look at us like we're nuts for traveling with such little ones, but I think babies are the easiest! They enjoy all the bright colors and sounds.
I hope you have a wonderful time, and if you'd like to discuss this more, feel free to send me an e-mail (chevelles@earthlink.net) or send me a PM.