Please don't ever put Bridget in a situation where she might bite your grandchildren. Even a tiny Yorkie can do serious damage to a child's face. A woman who works at my doctor's office adopted a Maltese who bit her husband in the face when he rolled over into "her space" in bed. He needed plastic surgery.
I have young grandchildren, too, (2 & 6) so I know how difficult it can be when they visit. I would keep Bridget safely gated or penned away. I would especially not have her on your lap when your grandchildren are around as that's when she gets aggressive, right? She considers you a resource and is guarding you.
I would start doing the NILF program with her as a dog who resource guards can be a ticking time bomb.
Nothing in Life is Free Dogs: Positive Reinforcement Training : The Humane Society of the United States