Let her kiss my baby?

My mother in law always has cold sores, I’m not sure why but she is just prone to them. I won’t let her kiss my two month old and she doesn’t understand why. It also might have to do with the fact that she tried getting me to have an abortion when we told her our news. She has apologized but it still hurts and I haven’t yet forgave her. My official reasoning for no kissing is that I’m her mother and I fucking said so. My low key reasoning is that it kills me seeing her interact with my baby after all of the horrible things she said. But my logical reasoning is that Poppy is a baby who’s immune system is still in progress, and cold sore Cindy doesn’t need to be kissing her. Let me know if I’m overreacting 😓