If I were to get another young female, I would spay at 5 or 6 months of age. There is plenty of research that indicates that if you spay before the first heat the pup has a zero chance of mammary tumors. There are also many other health concerns you will avoid. There are many, many studies on this and lots of information all over the web.
I adopted my Pippi when she was 10 months old and she had already been spayed previously. She is a 7 year old healthy, well adjusted pup! She actually is one of the most laid back pups in my home.
Just a few links:
Canine Spay FAQ - VeterinaryPartner.com - a VIN company! Spay/Neuter Info - Animal Birth Control Clinic : Waco, Texas - The Heart of the Solution ASPCA | How Will Spaying Change My Dog? Spaying or Neutering Your Dog FAQ Veterinary Q & A - Spaying (ovariohysterectomy) in Dogs and Cats - learn about spay surgery in dogs and cats
As for after care, your vet will advise you. She should be kept as quiet as possible...no running and jumping. They recover really do recover quickly.
Another thing to think about.... are her baby teeth all out? If not, you may want to have the vet remove them at the same time...or put if off another month or so.
Good luck!