Hi Leticia,
How wonderful to be taking your daughter to Walt Disney World for her 4th birthday! Since this is her first trip to Walt Disney World, I am sure that everything that you do will be special. I do have a couple of suggestions for making her birthday a memorable one.
First, be sure to get the birthday button for her to wear on her birthday. This button is free of charge and can be picked up at Guest Relations at any Walt Disney World theme park. It is so much fun, when your child is wearing the button, to hear cast members and guests wishing your child a happy birthday all day! You may also find that cast members might be able to give her a "magical moment" if she is wearing the birthday button. When my daughter wore the birthday button, she received a free surprise cupcake at the end of her meal at The Plaza Restaurant! This kind of magic is not guaranteed, so do not expect it, and if it does happen, then it is even more magical. Also, be sure to indicate when you are making dining or resort reservations that you are celebrating your daughter's birthday. Again, there is no guarantee of anything special happening, but you never know when magic may occur at Walt Disney World.
Also, you could consider visiting
Disney Floral and Gifts online. We had a plush Minnie Mouse holding balloons delivered to our villa at Bay Lake Tower at Disney's Contemporary Resort when celebrating our daughter's birthday. I suggest that once you browse their website, call them at (407) WDW-GIFT (407-939-4438) where you can speak with a Magic Maker who can customize a gift just for your daughter. Finally, consider calling the Cake Hotline at 407-827-2253, where cast members can help you to create a cake for your daughter.
I would love to help you plan further Leticia; however, I am limited in the space that I have to answer. Please do write back if you have any further questions!