The youngest I’ve take a child is 7 months, the oldest 6 years—my oldest didn’t turn 7 until shortly after our last trip. We’ve covered every age in between, some twice, as we have three and go every year. The easiest it has been on me is when they are infants. No age is more portable, content, and adaptable. I think the age when they have enjoyed it the most has been at three years. Each trip is different. Disney truly is for every age.
Changing diapers at Disney is no big deal. There is always someplace close by. At 7 months the characters sought us out and gave extra attention to my kids. Pocahontas actually got down on the floor and played with DS#2 for 20 minutes (no one else was there). And really, there is more they can experience than not. Of course, just people watching could even entertain my high maintenance, difficult child.
At 15 months my kids didn’t really know what anything Disney was. But boy, did they come home in love with Mickey, Donald & Pooh. The love for all things Disney has never left. New words included “Mickey”, “Duck”, & “Disney”.
At two everything was so real and they’re free. Everything is still real at three. They are meeting THE Mickey and eating in THE castle and riding in a REAL space ship shooting at THE Zurg. KWIM? And at three my kids could ride just about everything they were interested in and they *could* have ridden things they weren’t interested in—they were 40”.
By the time they were four, they were catching on to most things being magic—not that it was any less enjoyable or special, but… They also start getting whinier and more into what they like and dislike. It’s still wonderful, and not fitful, just not as worth standing in line to wait for 40 minutes to ride Dumbo or Goofy’s Barnstormer type of thing. But it does open up a time to introduce new experiences.
There is no way to do all of Disney in any one trip, so every age is great and different. Besides tomorrow is not guaranteed.