Hello Jacqueline,
We took our daughter to Disney her very first time when she three years old. It was such a memorable trip that I will cherish forever. I really believe you'll feel the same!
There's so much to do for little Princesses at Disney World. The question really is what wouldn't she do?
Magic Kingdom is fabulous for toddlers. There's Dumbo, The Many Adventures of Winnie the Pooh, and It's a Small World. And of course, you can now meet Mickey Mouse at the Town Square Theatre. The Princesses are next door too! Or your daughter can pose with Rapunzel in Fairytale Garden.
The other Theme Parks have attractions your daughter will love as well. She'll enjoy being a guest of Beauty and the Beast - Live on Stage at Hollywood Studios or going under the sea in the Voyage of The Little Mermaid. Your family will be sure to dive right in at The Seas with Nemo and Friends in Epcot. And my daughter never misses Camp Minnie Mickey at Animal Kingdom.
And those are just my suggestions for attractions inside the Parks. I didn't even mention
Bibbidi Bobbidi Boutique or
Chef Mickey's or
The Crystal Palace!
Although I will say this - while I enjoy all of the firework shows at Disney, we often skipped them when my daughter was younger. Midday breaks and "early" returns to the Resort for some R & R were important for us and our sanity. You know your daughter. If you think she can make it past bedtime to watch Wishes, I say do it! But if you think you might be chancing a meltdown, you might want to consider hanging poolside instead.
No matter what you choose, I'm confident your family will have a magical time! Good luck!