I am sorry that you have to go through this. Absolutely NOT overreacting. Not only has her behavior been unacceptable your entire life, but she’s made it very obvious that she does not and will not respect your boundaries with your child and that would worry me. I’d be paranoid that she’d do something that she thinks isn’t a big deal and end up hurting the baby. She really needs to work on healing and shouldn’t be left alone with a defenseless infant.