Hey Amanda!!!!
WOO HOO - You are planning your FIRST Walt Disney World Vacation! Your family is going to have so much FUN! Since you are only going to be at Walt Disney World for three days, I would recommend going to Magic Kingdom, Animal Kingdom, and Hollywood Studios. EPCOT is an incredible Disney Park, but I think the other three have more to offer families with small kids.
Here are my MUST DO's for your incredible family:
Day 1 - Magic Kingdom:
* ALL of Fantasyland
* Buzz Lightyear's Space Ranger Spin
* The Magic Carpets of Aladdin
* Tomorrowland Transit Authority PeopleMover (a.k.a. TTA)
* Wishes Nighttime Spectacular! (AWESOME Fireworks)
Day 2 - Animal Kingdom
* Affection Station (Really cool petting zoo)
* Kilimanjaro Safaris
* The Boneyard (another HUGE playground!)
* TriceraTop Spin
* Finding Nemo - The Musical
* Festival of the Lion King
Day 3 - Hollywood Studios:
* "Honey I Shrunk the Kids" Movie Set Adventure (HUGE playground...so fun!)
* Disney Junior - Live on Stage!
* Toy Story Mania!
* Voyage of the Little Mermaid
* Beauty and the Beast - Live on Stage!
If you have other questions, please let me know!
Have a MAGICAL day!
Wes