@AhMummy we got my four year old’s out this summer. I think our biggest regret was not giving her enough of a heads up to ask questions, read books, etc. so she had a tough time afterwards. I wish we had told her at least a week, maybe two in advance- but this depends on your child and what might work best for them. One thing that did help was taking her to pick out a ton of ice cream the day before!
She loved the Franklin Goes to the Hospital book, although I don’t know if that’s a little young for a 6 year old or not.
I know some people feel like (to an extent) the younger the better, but I actually think being 6 instead of 4 may give your kiddo a better chance at understanding what’s going on and being able to express when they’re in pain afterwards, which would’ve helped.
Stay on top of pain meds, even if it means waking them up. Don’t wait for them to ask for it. At least for us it was really hard for her to express the pain and I think it was surprising to her.
Good luck, feel free to ask me other specific questions if you have any and if I can answer I will!