I went through this with my daughter too.
The hospital will inform you of everything. Main thing it to keep her hydrated and calm and not to cry or talk loudly. Typically kids bounce back really well. If your insurance will cover it have her stay overnight, that it the most crucial time that first 24 hours. Otherwise follow the instructions of your Dr. She will be sore, it will hurt, they typically give them something for the pain but it is not horrible and she will be herself within a few days. My daughter was asking for pizza by day five after the fact. Keep lot's of yogurt, ice cream, jello and soft cooler foods on hand. Lot's of gatorade and Pediasure too.
I actually took my daughter to the hospital and showed her where she was having surgery, I explained they would put a mask on her face with air that will help her rest (this can be the most scary for the kids and best to prepare them ahead of time), you can be in there until she is asleep with her and then they will call you when she is coming out of the anesthesia. That is the hardest part, they are disoriented, scared and very out of it. Expect some crying but try to keep her calm and just hold her. The meds wore off within 12 hours after surgery and my daughter then threw up due to the anesthesia upsetting her stomach, so that wasn't good. They gave her some anti nausea meds then and some mild pain relievers. She stayed overnight and I slept on a cot in her room though. It was easier having nurses very handy to help me make her comfortable.
Good luck, she will feel so much better after they are out!!!!