Hi Erin and welcome to the Disney Parks Moms Panel.
I can't think of anywhere more perfect to celebrate your daughters 5th birthday.
First things first, be sure to pick up a complimentary "I'm Celebrating!" badge as you enter the first Disney Park that you visit for your daughter to wear during your stay. You will often see Cast Members handing them out as Guests are entering the parks but if not, they are available from all Guest Relations locations.
You will be amazed at how many Cast Members and other Guests will stop to wish her a happy birthday and make her feel extra special.
I would also suggest that you book a Character Meal at either
Cinderella's Royal Table at the Magic Kingdom park or
Akershus Royal Banquet Hall at Epcot as a special treat to celebrate. At both of these restaurants you will be able to meet a number of Disney Princesses whilst enjoying your meal.
As both of these restaurants are extremely popular, I would highly recommend that you make an Advance Dining Reservation for your desired date at your earliest possible opportunity.
Advance Dining Reservations can be made up to 180 days prior to your visit
online at the Walt Disney World website or by calling 0800 16 90 748 from here in the UK.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma