Yes, it's not good for your PUPPY TO HAVE PUPPIES at one year of age. A toy dog isn't fully grown until a year of age and a larger dog isn't fully grown until about a year and a half of age. Dogs shouldn't be bred until they're about two.
If your dog has no complications from birth, she will probably not have any problems from having puppies at 1 year old. It can take a toll on their long term health. I would recommend speaking with your vet about this.
Responsible breeders wait until their dogs are at least two. It's bad for her and she needs health tests to be make sure she's not passing any genetic diseases on.
Ideally, a dog this young would not have puppies, however, if a dog winds up getting pregnant on her first heat, it is not the end of the world. She should be watched carefully to make sure she has no complications.
