The ones I know seem to be good with children, of course they were well socialized. They aren't the least bit nippy. The only problem I see in getting a small dog around small children is that the kids are the ones who tend to hurt the dogs. She's going to have to watch her children and teach them how to be gentle with a small dog. They are going to see this little puppy and see a rag doll to dress up and play rough with, or a small puppy to put in with their toys. She'll have to get a little pen or crate when she can't supervise them together, but she should have a puppy area set up anyway. She'll have to work with the puppy to not be food or toy aggressive. I'd say if she's ready for a shih tzu, grooming and puppy training and all, and she's going to watch her kids, then she's picked a good breed.