Hi there, Nathalia!
Cumpleanos felices! There is no better place to celebrate a birthday than at the Walt Disney World Resort.
When you arrive at your hotel, make sure to tell the Cast Member who checks you in that it's your birthday! You'll receive a special free birthday pin that you should wear for your entire visit. You can also ask for pins for your whole family that say "I'm Celebrating!" so they can join in the fun along with you.
Throughout all four Parks, you will find locations where you can meet characters, including favorite Disney princesses. They can always be found at the Town Square Theater in Magic Kingdom; you can also make a reservation to dine with them at
Princess Storybook Dining at Restaurant Akershus in Epcot's Norway pavilion.
Make sure you pick up a map and a Times Guide each time you enter a Park. That will give you the most current times and locations for meeting characters.
And don't forget -- Mickey Mouse loves to celebrate special days with his Guests; make sure to stop by and get a birthday hug!
See you later, celebrator,
-Deborah B.