Oh, Amanda! We are just the same---Amanda's and babies, that is! I have taken my 9 month old daughter to Disney World and my 7 month old son. It's not as hard as you think and your son will have more fun than you think!
The characters, the shows, the music will be super attractive for him--so big and colorful. I remember sitting with my son at The Festival of the Lion King and him loving it. Of course, I had tears in my eyes because I was sharing such a fun time with my son---he'll never remember it but I will!
The good thing is at 7 months old, he'll still fall asleep easily. Both my kids slept through fireworks and through most meals. So, in one way it's easier than the toddler and preschooler that needs a real nap!
Two of your best resources (besides your stroller and/or sling!) when taking an infant to Disney will be the Baby Care Centers (an air conditioned haven with changing tables, high chairs and private nursing areas) and the
Magical Beginnings map (a map showing the must-dos for little ones).
Enjoy your first Disney trip with your son!