Hi Jen,
How exciting to be planning your first trip to Walt Disney World! Let me suggest a couple of planning resources for you. Be sure to watch the
Walt Disney World planning video. This will allow you to see the theme parks and think about which ones look the best for your little ones. I also suggest that you take a look at the
Walt Disney World with little ones planning page. This page offers tips specific to traveling parties with young children.
That said, I definitely suggest that you visit
Magic Kingdom. It was the first Disney theme park in Florida, and is what most guests associate with Walt Disney World, including the iconic Cinderella Castle. When my daughter was little, she loved a ride on it's a small world. There are so many characters to meet and attractions to love at this theme park!
I also think that given your children's interests, a trip to
Disney's Hollywood Studios is in order. This is the headquarters for all things Disney Junior and Pixar! Check out Disney Junior - Live on Stage! for a rollicking fun show. I remember watching my daughter dance with delight at this show. Toy Story Mania! is a fun attraction featuring many Toy Story characters. There are character meeting opportunities for both Pixar and Disney Junior characters at Disney's Hollywood Studios.
There is something for everyone at every Disney theme park, so do take a look at Epcot and Disney's Animal Kingdom to see if you think your family would like some time at those theme parks as well.
I would love to help you plan more Jen; however, I am limited in the space that I have to answer. Please write back with any further questions!