Disney can be a great experience for children of all ages. A few things from a mom who has been to disney with a 7 month old...
1. Make sure you pack lots of extras...breathable clothing, formula or baby food (in case you aren't breastfeeding), baby sunscreen (I re-applied every hour!), easy to transport toys (mine loved to play with the fan/water mister we bought at disney and plastic keys), a stroller with a canopy, and hats.
2. Avoid carrying your child without a harness or pouch. I carried my daughter in a harness in front of me when she wasn't in her stroller. Your body heat will only make her heat up faster. Oh, buy in advance and break it in. Otherwise, your child might not be willing to get into it when the time comes. Also, it is important it is comfortable for both of you.
3. Take advantage of baby centers when feeding time and diaper changes come. This gives you a break from the bustle since they are quiet and darkly lit.
4. Buy sun burn detection stickers. They are available where sunscreen is sold at places like target and
walmart. When we returned from our week, our daughter had a slight tan...no burn! Of course, I lathered her up constantly and kept a hat on her all the time. BTW, she is one to burn usually.
5. Take a break during the heat of the day. You can find a nice quiet place in the shade, go back to the hotel, make use of the baby centers. However, if you still want to explore during those hours, make a trip into one of the many inside exhibits. Just avoid going in and out of air conditioned buildings. That is hard on a baby.
Don't feel like you are doing the wrong thing by taking your baby to disney. Our daughter may not remember her first trip, but she loves looking at the pictures and hearing all the stories about it. It has made preparing her for this trip a little easier, too.
Good luck!