There are a few things you can do:
1. Make special dining ressie to her favorite place and make sure they know it's her b-day.
2. Order a cake for her ahead of time to be delivered to the restuarant.
3. Make sure to get the birthday button
4. When I was there during my b-day I had a shirt made that said "Having A Tiggerific Birthday" on the front and "Today's My Birthday" on the back. If you have a shirt for her then the rest of the party could wear "today is my un-birthday" shirts or "I'm with the birthday girl"
No matter what-have fun!