Hi MaryKayKay! Welcome to the DIS!
A suggestion would be to take your dd to one of the character meals for her birthday. At many of the charactr meals we have attended we have seen(and experienced first hand) "the Birthday Big Deal". At Chef Mickey's the characters all twirl napkins and sing, at Crystal Palce Tigger, Pooh, Eyeore and Piglet have a parade, often lead by one of the birthday children at the restaurant, others are often lucky enough to be a part of the parade banging tambourines or little drums.
Even if your daughter feels she is too old for a character meal I'm sure she will love the attention where ever you plan on going... just make a note of it on your Priority Seating(PS) and let the Cast Member(CM) know that you are celebrating a birthday. Sometimes a cupcake will arrive and CM's may sing happy birthday.
If you really want to make it special you can preorder birthday cakes at some of the restaurants for around $10(not quite sure about the price, maybe someone else knows?).
All in all, you are at WDW and your DD will love celebrating her 13th birthday.
Have a great time!