Hi Beth!
Congrats on securing your first trip to the "Funnest Place on Earth!" All trips are fantastic, but that first trip is always extra special. As Mickey would say, "Hot Dog!"
I'm glad to hear you've reserved 2 days for Magic Kingdom. I always tell guests to get the full experience of Magic Kingdom with your family it generally takes 2 days to do, when you factor in the dining, parades, shows, meet-n-greets, and of course, the attractions.
You'll be surprised to find that Magic Kingdom is so massive, you may go the entire 2 days without getting on many of the rides twice. However, having myself a 3 and 6 year old, here are the rides they wanted to get on multiple times:
Buzz Lightyear's Space Ranger Spin
Mad Tea Party
Mickey's PhilharMagic
Dumbo the Flying Elephant
Magic Carpets of Aladdin
Tomorrowland Speedway
If you have time, you're sure to get a second request on some of these :-)
Hope you guys have a wonderful time!