I think any age works, but we waited until my daughter turned 5 and did a huge, no-expense-spared trip for her birthday week. If there is a perfect age, I would say it's that and I say that knowing that 5 people could respond to that question with 5 completely different answers. She was in awe of everything even without a wide knowledge of all things Disney, loved the characters, had the stamina for the marathon days, and didn't get real antsy waiting in lines (she's probably worse with that as a 13 year old). She's a competitive cheerleader so we've gone every spring since 2021 and we leave for her 6th trip in 9 days. Getting in a couple of trips early on has made these more recent trips a lot more fun. We pick and choose what we like to do and we don't have the nagging feeling that we have to do all the things. At the end of the day it's Disney. Even if you screw it up, it's still better than a good day at work.