Hi Jolene,
A trip to Walt Disney World during the holidays is definitely the most magical time of year to visit and with the added celebration of your daughters 5th birthday, it sounds like you are in for a fantastic time!
There are many ways that you can celebrate her birthday such as:-
1/ Make a dining reservation for a Character Meal and pre-order a custom cake to be brought to your table during the meal
2/ Arrange an In-Room celebration or Mickey's Birthday Surprise through Disney Floral & Gifts
3/Arrange for a gift to be waiting for the birthday girl upon your arrival at your Disney Resort hotel through Disney Floral & Gifts
4/ Create your very own Birthday Ear Hat at the Chapeau in the Magic Kingdom theme park
5/ Make an advance reservation at the
Bibbidi Bobbidi Boutique where the birthday girl can be transformed into a Disney Princess
You will find lots of other ideas on the Customize Your Special Occasion page of the Walt Disney World website
HERE.
I would also be sure to pick up a complimentary birthday button when you check-in at your Disney Resort hotel or from Guest Relations as you enter one of the Disney Parks for her to wear throughout your stay. You will be surprised at just how many Cast Members and other Guests will stop to wish her a Happy Birthday.
I hope that this has given you some ideas and wish you a magical trip!