Hi:
It won't hurt her to dose the K9 advantix now. If you are having a flea problem consider adding capstar tablet to your dosing regimen. You can purchase this from your vet as well. Here is a website regarding capstar - scroll down and click on capstar:
http://www.adequancanine.us/about/en/faq.shtml
Dr. Debbie
Veterinarian
Full time practicing companion animal veterinarian.