Hi Jessica,
If I only had one day at Walt Disney World, my first choice would be the Magic Kingdom.
With the ages of your kids, there is something for everyone!
From the attractions, character meet and greets, parades, fireworks you cannot go wrong.
I think for a first visit the
Magic Kingdom is the place to start. There is so much history along with cutting edge innovation it truly is an amazing experience.
I suggest you start early and finish later with
Wishes Nighttime Spectacular Fireworks
You can't go wrong with any of the parks.
Thank you for your question. All the best with your decision--have a magical vacation!
Carrie