I would suggest spaying her.
Its really not that big of a surgery. I have had 10+ dogs (mine plus several fosters) altered and all have bounced backed without any problems. I had Laney done at 3 mnths old and she was only 3 lbs and was fine the day after, in fact I had to keep her crated to keep her activity level down b/c she was wanting to run and jump everywhere.
It eliminates the possibility of her getting uterine or ovarian cancer. And if she is spayed before her first heat it even reduces her chance for breast cancer.
We recently had to see our 20 yr old suffer from cancer bc she was never spayed (but never had puppies) and it wasn't a pleasant experience to say the least.
Here is some more info on it:
http://www.hsus.org/pets/pet_care/wh..._your_pet.html