Our 5-year-old son shares a similar history, and we finally had his tonsils and adenoids removed. We were anticipating the worst recovery - and were very surprised when he was up and playing as soon as he came home the first day. He refused to take pain medications after the first dose (request something that is flavored to hide the bitterness) and rarely made any complaint of pain or discomfort. He would nap more than normal the first 3 days, and he had an appetite from the start. I guess the lesson for us is that children are incredibly resilient!
Our advice to your daughter would be that even though it may be scary, this is a big adventure for her that will make her feel SO MUCH BETTER when it is all over. Julian has not experienced any ear infections now in over a year, and is so much healthier now that he's been through this procedure.
Perhaps you could take her to the grocery store to let her shop for her special foods for after the procedure - special soups, popsicles, pudding, applesauce - things that could be swallowed easily without scratching the throat. Also, you may take her shopping for a special nightgown and slippers that she can wear when she gets home, and you can set up a special "recovery room" in your family room where she will feel like she's the center of attention. Take her out to rent a few movies she can watch while she's resting and recovering, and perhaps with all of those special items, she'll feel more comfortable about going forward with the surgery.
Lastly, if it would be of any help, we could arrange a meeting where she could meet Julian and she could ask him questions. She could even look at his throat to see how it is different than hers, and they could talk about whatever concerns her.
Our only regret is that we didn't have the surgery sooner. It has been a blessing to see Julian healthy and happy after years of tubes and infections.
Good luck!
S.