I'm sure she's sturdier than she seems, especially if you can mistake her for a football

Seriously though she must have had her first heat by now right? When was it? I would wait until it was 3 months past that heat and book the spay. They might also be able to do part of the dental work at the same time.

I would then wait at least 6 months before putting her under again. Unless of course the surgery was urgently needed.