Hi Tammy!
Walt Disney created Disneyland with the family in mind. Even though he didn't live to see it's completion, the same family foundation was carried over to The Florida Project (aka Walt Disney World).
We've traveled with an infant as young as
7 weeks (yes, seven weeks old!), and he was able to ride 98% of the rides at Walt Disney World (there are so many!). Here's a list for you of attractions that have a height requirement that the little one won't be able to ride. As you'll be able to see, it's just a handful in each park:
Magic Kingdom
Big Thunder Mountain Railroad
Splash Mountain
Space Mountain
Stitch's Great Escape
Tomorrowland Indy Speedway (riders need to be 1+, and someone will need to ride with an adult so they can operate gas pedal and help steer)
The Barnstormer
Seven Dwarfs Mine Train (once it is opened)
Epcot
Soarin'
Mission: Space
Test Track
Disney's Hollywood Studios
Tower of Terror
Rock 'n' Roller Coaster
Star Tours
Disney's Animal Kingdom
Expedition Everest
Dinosaur
Primeval Whirl
Kali River Rapids
Have a magical vacation!
Amanda