Am I wrong?

**First off this is not a pit bull bashing post. I have a pit bull and they are my breed of choice.**

Here's my baby:

So 4 years ago my Step-Dads pit passed away and in his grief he bought a pit puppy that didn't have any papers or bloodline history on a sur of a moment deal. So yesterday the dog bit his 13 month old baby girl in the face. She didn't have to go to the ER but it did draw blood and leave marks under her eye and on her jawline. This is the 7th person the dog has now bitten. 1 person had to go to the hospital and have over 20 stitches because of this dog. Its like a flip switched in the dog a few years ago, I refuse to be around it due to its aggression towards me. So my Mother has decided to take the dog in as she has no small children. Thing is I have an 8 month old that I take to visit her weekly. I told her that I will no longer bring my son to her home since she has decided to take in the dog. I told her it needs to be put down. She got very defensive and says I'm overreacting. Am I wrong? Its not that this is a pit bull, its that this is a large dog that has bitten 7 people including a baby.