[Ellie May]

I think I'd have bloodwork with a Spec cPL done just to make sure everything is clear.

Anesthesia is scary stuff, but for most dogs, spaying is in their best interest. It is probably too late to change her % chance of developing mammary cancern, but spaying would prevent pyometra. If this occurs, she will very likely need an emergency spay while being very sick which would be so much harder on her. Have you talked to the vet about your concerns?