I think she will be just fine. I also believe you are doing the right thing by having it done in Nov. Five months is not too soon. In a few cases, they do go into heat early and you don't want that to happen. That just increases the chance of cancer later in life. There are lots of tiny one's on here that have been spayed and came through it just fine. I certainly understand your worry. It's natural to worry like that. I certainly did. My puppy and I were equally ecstatic to see one another afterwards. Kacee was just spayed on October 21st.