It can be very confusing when you first come into the hospital. Then you'll want to know where you will go next. Usually there is an area called surgical admitting. The next step would be going to what's called the pre-op or holding room. You can ask what that is like.
Hospitals do vary a lot according to the size and also if they handle many children.
Usually adults receive some medication and even intravenous fluid in the pre-op room but that might not be the case for children. The needles and medicine may only occur once she is in the actual operating room. So it's important to ask about that. Intravenous fluids are pretty automatic in all surgery. But you need to go over this some more with your doctor.