Hello, Kristin!
What a wonderful surprise for your daughters, especially the birthday girl!
We've often found a little more luck when booking Walt Disney World Dining Reservations fairly close to our arrival by checking out those restaurants which are located outside of the four major parks, or a restaurant you may not have heard of previously. We've found some new favorites this way, too!
On
Walt Disney World's online dining reservation page, I checked out the date you listed and found six Walt Disney World restaurants which offer Character Dining and have availability for a party of five anywhere from 3:30 p.m. until 6 p.m. (I had selected 5:00 p.m., just to see what's available for you.) These included: Akershus Royal Banquet Hall; Cape May Cafe; The Crystal Palace; The Garden Grill Restaurant; Garden Grove and Hollywood & Vine.
You can also contact (407) WDW-DINE and ask a Cast Member to make some suggestions for you, since he or she has been booking that date recently and may recall which locations seemed to have had availability. This has been a great resource for us as well; Cast Members love to help!
Don't forget to tell Dining that you are celebrating a very special day: the first double-digit birthday!
Wishing your birthday girl and her sisters the most magical of celebrations!