>- When cuddling, she also takes my hand and wants to be touched there, and laughs when I refuse to, asks me "why not?"
I agree with the other posters that you should not sit idly by in this case.
You must first explain to her that "no one should touch her down there". Just like being in private when she touches herself, this part of her body is private to her and no one should touch it. The exception being a doctor when you are present.
Second, ask her about this "anna", including age, characteristics, etc. Even an older person might have posed as a schoolmate. It could be immaginary but it is very important to find out as these things can affect us for the rest of our lives.