I don't know what to do! Brianna just turned a year old, and she just got her first heat. I am so confused because I do not know if I want to get her spayed or not! But the vet that I am taking her to is telling me that if I want her to keep being his patient that I have to get her spay. I really do not know what to do. I really like this vet and I trust him with the girls. but I think that it is my decision if I want to spay my girls or not.

What should I do?
Here are some pics of Brianna. And another of Brianna and Gracie!