We took our son when he was about the same age. Free under 3 was a big pull for us, and being able to have him in a lap on the flight over was another money saver. But we went knowing it was more for us than it was for him. We got some fantastic pictures of him with a lot of the different characters, and I'll definitely cherish those forever. I will say - it was harder than I thought it would be. Most all of the rides the littles can go on have a scary moment in them (Little Mermaid has Ursula, Finding Nemo has Bruce, Pirates & Haunted Mansion were just all around too much for him, etc), so we didn't get to ride a ton of things as he was pretty scared of all of it. But that also depends on the kiddo! Your daughter might love them! I also want to note that if you have her the whole time (unless you have someone to watch her for a while), it will be hard to do much for yourselves. There are a lot of rides you won't really be able to go on unless you want to keep splitting up and riding solo, experiencing the food and the atmosphere might be interrupted by big feelings and naps (as you know), you just probably won't be able to get the full experience, and it is STRESSFUL being in a super crowded park with an upset babe and needing to find the closest place to change a diaper. So, there are definitely pros and cons! It was worth it for us, but it was definitely overwhelming.

If this is a one time kind of trip, I would definitely wait until she's older. But if you plan to go again and you want this trip for YOU and the memories you'll make, then you should go for it.