Hi Shante!
I'm happy to be able to tell you that even babies get to enjoy all the Magic at Walt Disney World! There are many attractions with no height restriction that you'll be able to enjoy together! My own son's first visit was at 8 months old, and he was able to enjoy many attractions with our family.
In cases where your littlest ones are unable to ride due to safety restrictions, you can take advantage of
Disney's Rider Swap option, whereby one adult stays with the infant while the other rides the attraction with the older children. When they finish, the adults can 'swap' so you both get a chance to enjoy the attraction with the kids.
At Magic Kingdom, attractions the two older children may wish to ride for which you'll need to use Disney's Rider Swap option are: Space Mountain, Splash Mountain, Big Thunder Mountain Railroad, Stitch's Great Escape! & the Tomorrowland Speedway. You'll be able to enjoy
all the other attractions & shows in Magic Kingdom together and will find that there are many attractions for the whole family to enjoy in the other parks too!
Be sure to visit the
'Attractions' page for all Four Parks to view detailed information about each individual attraction. Those listed as 'Any Height' indicate that your littlest ones will be able to enjoy the attraction while seated safely on the lap of an adult. You can also sort attractions by Height using the handy menu option on the left side of the web link.
Wishing you a simply Magical time on your Walt Disney World vacation Shante!
Kirsten