Having your tonsils out as an adult,is indeed a bigger deal than having them out as a child.
The operation may be technically marginally more difficult than for a child but the post operative recovery is more prolonged and more painful.
It there are no complications, you should be in hospital for 2 days.
You will arrive in the hospital starved from the night before, you will be checked by the Anaesthetist and when it is your turn, you will be taken on a trolley to the theatre.
An oxygen mask may well be put over your face, whilst the anaesthetist gives you an injection into your arm and within 8 secs you will be asleep.
Main problem after the operation and for the next 7days will be difficulty in swallowing and earache. To minimise these, eat solid foods and not just soft food.
No bladder catheter should be necessary.
Good luck