Hi Anais,
Happy Birthday to your daughter! Seven is such a great age! Make sure you grab a Happy Birthday button at your resort or parks so people know you are celebrating.
Cinderella is known to dine at two places. She invites guests to dine with her at
Cinderella's Royal Table for breakfast. This is one of the most difficult reservations to get so look on line for a reservation or call Disney Dining at 407-WDW-DINE. If you do not have success, you can try a walk up reservation but you will need to be at the Magic Kingdom as soon as it opens. They still may not be able to accommodate you but it is worth a try.
For dinner, she likes to dine at
1900 Park Fare in the Grand Floridian as she host Cinderella's Happily Ever After Dinner. This is one of my favorite character meals with good food and great character interaction. The Evil Stepsisters are hysterical. Again, try a reservation online, by calling or walking up to the restaurant as soon as it opens.
You can also also meet Cinderella & Rapunzel at Princess Fairytale Hall in Magic Kingdom.
Wishing you a magical vacation!
Beth