Hello Constance! Welcome to the Disney Parks Moms Panel.
How exciting that you will get to experience the Endless Magic of a Walt Disney World Resort for the first time with your little Mouseketeers. I remember the first time my family walked into Magic Kingdom with eyes wide and giddy excitement difficult to contain. My kids were excited, too!
As far as selecting from the four Walt Disney World Theme Parks is concerned, I would have to pick Magic Kingdom for day one and either Disney's Animal Kingdom Theme Park or Disney's Hollywood Studios Theme Park for day two.
Magic Kingdom is the be-all and end-all Theme Park and a must-visit on your first Walt Disney World Resort vacation. There is enough to keep kids of all ages consistently engaged and the varying lands offer a broad appeal all within the same Theme Park.
For the second day, I would choose
Disney's Animal Kingdom Theme Park if any of your kids are animal lovers or have an interest in experiencing
Pandora: The World of Avatar or
Disney's Hollywood Studios Theme Park for kids that are more interested in experiencing a nice mix of entertainment that includes Disney Jr. Characters,
Star Wars or the Disney movies, in general.
Have a blast on your first Magical Visit!
~Todd