Hi Nichole!
Those are great ages for the children for a trip to Walt Disney World. Without a doubt, you will want to visit the Magic Kingdom. Not only is it the crown jewel of the Walt Disney World Resort, but it also has the most to offer young children. After that, I would suggest visiting Disney's Hollywood Studios. While its most popular attractions will be too much for young children, it also has a lot of attractions, especially stage shows, that will appeal to young girls.
Be sure to make Advanced Dining Reservations (ADRs) for any Table Service (full service) restaurants you are interested in. ADRs are critical especially during a busy month like April. Without them you will be hard pressed to get into the Table Service restaurants, especially the most popular ones. ADRs can be made online or by calling (407) WDW-DINE. I suggest considering some Disney Character Dining Experiences as well:
- Chef Mickey's in the Contemporary Resort
- 1900 Park Fare in the Grand Floridian Resort
- Crystal Palace in the Magic Kingdom, especially if you have big Winnie the Pooh fans
- Tusker House in Disney's Animal Kingdom
- The Garden Grill in the Land pavilion at Epcot
By the way, I highly recommend picking up the book "The Complete Walt Disney World" by Julie and Mike Neal. It's a great book for first time visitors as it has a lot of information, but is not overwhelming. It is also a beautiful book full of color photographs. It will give you a good feel for everything there is to do at Walt Disney World.
I hope this helps to get you started. Write back with more questions; you can send them directly to me!