Salazark, I know what you mean. Most vets traditionally say 6 months. Rescue groups and other organizations push it as well. And in fairness to them, to reduce the population of unwanted dogs from both unscrupulous breeders and irresponsible pet owners. So, I can see it from their prospective as well. However, I don't think they really consider the risks of toy dogs being spayed at such young ages.
However, I am beginning to believe that Molly would fare much better if she were older rather than now at 7 months. I am starting to believe because of their small bodies to begin with, it is best to wait to give them a chance to both grow and to mature first. Even my daughter (I hear it from her too. Except that she also accepts and understands that it might be more advantageous for me to wait in having Molly spayed.) is doing her dog this month. But then again she's a 15 lb healthy 10 1/2 month old pug. So, I'm sure she'll fare just fine. The best of luck to you in your decision as well. Although at the same time I kind of dread dealing with her in her first heat. Perhaps, it won't be so bad.