Dogs can become territorial over their space. Putting them in the cage, only after 2 weeks, was a mistake.
I would say you don't have to get rid of her. I would just never get another animal, especially dog, with her. She is probably dog aggressive if it reached that level of severity. With the child, I would never let any dog around them at that age alone. A child can do things that dogs won't like, even though the child doesn't realize it. It's not a big deal, but I wouldn't leave the child alone with the dog ever. I would stay close or keep them apart until the child is old enough to know what to do. You never know with animals so it easier to play it safe.
My old neighbors kid was playing with popcorn and their dog bit him and ripped a piece of his nose off trying to get the popcorn. She wasn't even trying to bite him. They got a puppy, much smaller than the big dog that bit the child. The big dog grabbed the puppy twice, by it's head, and shook it causing the puppy to get stitched twice. They had to put the dog down after that. I wouldn't tell you to put her down because she only seems aggressive with other dogs. Just plan on not getting another dog and supervise the child. And in the future, always introduce your current pet to a new one outside of the home a few times before bringing the new pet into the home and the other dog's space.
Years of owning various animals and neighbors experience with their dog attacking their child and other dog.