Sometimes when you leave a subject alone it will come back again when you're ready. I suspect this will happen with you. I understand "wanting to figure it out". I wish very much I could figure out why I am the way I am but I can't. My T thinks EMDR will help get me unstuck and uncover some childhood issues but I don't like EMDR too much. We have to do it occasionally, not often.

So, go ahead and plan your session but let what comes up, happen. I always used to come in with my agenda, with my former T, but my new T didn't like that. Therapy is much more spontaneous and I'm getting to feel my feelings, but it's much more intense and scary. I agree with not talking about what happened with her boundaries and phone calls again if it's not productive. I also wonder if you need to discuss her fees about the letters when you were away so it doesn't become a barrier.

About your childhood. Do you have photos to jog your memory? Letters? Anything? I wonder why you wouldn't recall much of your childhood. I hope you have a good session. Sometimes lighter, positive sessions are good for you!