Your Princess will do just fine with her spay. Maggie May was in a little bit of pain the first night and we were able to give her some pain meds-she quieted right down and went to sleep. The next day she didn't cry/wimper like the first night but she was definitely quiet and stayed in her crate. By the 3rd day she was just about back to normal and being her little terror self.
Maggie was just under 4 lbs when she was spayed.
It was a little bit of a challenge to keep her quiet but overall it wasn't too bad as we have 2 yorkies.
I have a soft cone collar called the Kiss-E Collar if you might be considering a cone. Just click on the link in my signature and you can read up on them.
Best of luck with Princess' procedure. Let us know how she does.