That is a 100% what a narcissist will do deflect from her faults onto yours and refuse to engage except in arguments and all out war.You think you are having a discussion with an adult whereby you will sort your differences point out the traits and behaviors you don't like come to an understanding and move on.Nope with a narcissist you are talking to someone who is all ego and like a five year old,gets upset and defensive and wants to argue win the argument be right,get to stay the way they are and not have to look at issues,looking honestly at self means reflecting and engaging feelings,they got no feelings,they can't empathize ,they can't see how you feel and care about that,they can't stand that they can't feel but they even more can't stand that you do and they need to to relate to you.So it becomes a power struggle thereby everything turns into a war for the narc to be right and convince you of that ,when she wins the war or argument and gets to be right then she gets to define how things are and how things are in her eyes is the problem is you not her.You aren't going to get through the thick brick wall that is the head and stubborn will of a narcissist.It is always going to be a power struggle to them whereby they have to win this power struggle and be the one in charge.
Also if you have let her down in the past then she views it as you owe her and are the one in the wrong,then ,now and always, one mistake whenever you make it will be held against you forever in the eyes of a narcissist,once your fault always your fault.