Hi C.!
It's a hard decision isn't it?
My son had this surgery at the same age as yours ( about 9m ago).
We were told the biggest problems with the recovery was dehydration because the scabs get so uncomfortable. We did have to "force" our son to drink fluids (we made it a game). The other hard part was keeping him entertained and giving the meds for pain. They get scared of swallowing something when their mouth is so painful, and he just wanted to lay around so he needed activities to keep his mind off of the pain and limit TV time.
So we loaded up on educational movies, sticker books, free magazines (to cut out pics, or circle pics) new coloring books, etc. Made his recovery room our down stairs couch so we set it up fun (favorite sheets, all his animals,etc). we explained to his bro how to help take care of him (read to him, color with him, bring him toys,etc) and the same for visitors (we limited who came). Also load up on popsicles, slurpies (maybe get a fun cup) etc.
Also when she goes into surgery, I think they prefer they wear disposable underwear incase they get a little sick and you can change them easily. Load up and dress her in comfy easy to change clothes. She won't want to move or change and if she gets sick (vomit). Which b/f I forget, my kid didn't, but my neighbors vomitted on they way home so bring plastic bags (and again) easy to change clothes.
For the first week he stayed in his bed/couch and slept on and off. It was spring so we took him for comfy/easy walks just to get him out. After the second week if gets tough b/c you have to limit activity so the scabs don't open and they start to feel alot better and want to do more.
Our son's voice changed afterward, and they have stinky breath for awhile!!
Sorry if these thoughts are scattered...trying to put it together fast and I know I was really nervous too. I know some kids healed like my son did, and others who were back to themselves the next day!!!
Please feel free to email me with other questions!