Hi Laurie and congratulations on taking your little Princess to her first magical visit at Walt Disney World!
Your question flooded me with memories of taking my oldest daughter to Walt Disney World for the first time when she was about the same age. She is 14 now, but still talks about that visit!
There are no "shoulds" when it comes to the topic of how to surprise your child and prepare for a Disney vacation. Your family is unique and likewise will have a unique vacation experience from anyone else's family. I'm so glad to be answering your question though, because I would love to tell you what we did for our daughter.
First, the surprise announcement. We sent our daughter on a scavenger hunt and at the end was a plush Mickey Mouse with an party invitation to visit him. However you could tailor the ending to be her favorite character or maybe even a
Frozen plush toy and talk to her about meeting Anna and Elsa. Whatever your choice is, be sure to capture it on video! I also created a countdown calendar so that my daughter could have an understanding of when this magical event was going to happen.
Great idea with re-watching Disney movies to get in the mood! We did the exact same thing and found it really enhanced her experience of the attractions and character interactions. Her favorites were the classics like Dumbo, Sleeping Beauty, Many Adventures of Winnie the Pooh, Snow White, Peter Pan, Cinderella, and Lady and the Tramp.
Here's to your First Disney Vacation!
Blessings,
Brenda.