Hi Saramoon, my dd2 had hers out last January at just over 2yrs...she was in for a night, but she needed an HDU bed anyway (restricted airway) so i'm not sure if that would be standard for slightly older kids with no other issues or not.
My tips would be to take a few clean tops for her, and for you, in case she's sick after surgery...some snacks and drinks for both of you (they try and get kids eating very soon after the op nowadays, toast and crisps rather than ice cream as rough foods promote healing...but dd did suck an awful lot of ice lollies for a week afterwards too), and if possible a portable DVD player with her favourite DVDs for distraction, or books.
Some kids bounce back amazingly fast, others are ok for the first few days then have a rough time between 5-9 days later (as scabs come off), my dd had a lot of pain for about 9 days. Do stay on top of pain relief, bang on time or even 20 minutes before - so the pain doesn't get on top of her, IYSWIM. dd had suppositories in the end, because she wouldn't swallow Calpol or Nurofen - and her hospital didn't give codeine.
I used an alarm to wake me before dd's meds were due at night.
dd1's friend has just had his out at nearly 6, and he was ok for a few days then had a very painful couple of days around day 7 - by day 10 he was up and fine and I saw him at a birthday party! Just look out for fever or bleeding, otherwise the pain can seem worrying but is really (as you no doubt remember) normal. And is far worse for adults, so hopefully won't be nearly as bad as you remember yours being.
Do try a search here, because there ahve been lots of long threads with experiences and tips - I can't remember half of it!
Good luck, it really is worth it