If I was going to say anything, I might say something like, "Yes, I do remember it because I was very hurt at the time but I have decided to put it behind me. However, if you want to talk about how you felt, I am ready to listen." Let her say what she wants to say, then if it is contentious and you can't discuss it without an argument, pass it off with a, "I'm sorry you feel that way, it looks like we'll have to agree to differ." You never know, if you listen with an open mind, you might find that she reacted the way she did because of something you did which she was hurt about. If that is the case, you can ask her what she thinks would be a better way to resolve things without an argument. I have found that with my grandaughter who has behavioural problems, that when we get to the bottom of why she reacted as she did, we can work out a strategy of how to avoid the argue in the first place. I see it as a way for her to learn how to negotiate her way through difficult relationships throughout life.