Both of my girls' spay days seemed VERY long, especially until I got the phone call that all was well and the time I could come for them. Try to stay busy and do your nails or something
It's hard, but she'll be okay.
Yes, definitely ask about the retained baby teeth. They can be removed while she's under. It's best to get them out so that they don't cause any decay in the new adult teeth (food gets stuck in between, etc.)
It's hard to believe that KS is already old enough to be spayed, time sure does fly!!!