I am not sure I agree with spaying too early. I normally prefer to wait 6-9 months before spaying, or sometime after their first heat. I have had a lot of small (rescued) dogs experience complications from being spayed to early and I have found that waiting until the dog is bigger not only gives it time to mature a bit but also makes it a lot easier to spay. Ultimately its up to you and the vet that you trust... This is just from my experience both from rescue dogs and breeding. If your careful and you watch her when she is in heat then you wont have any problems with accidental pregnancy (not to mention she most likely will not go into heat until the 6-10 month range).