I am not sure how I could have gone into my past in just one session. My therapy has been blending all of it together. We did a few sessions towards the beginning where I told her the big arching outline of my life and the who's who of my family of origin and current family. We then spent months weaving mostly through the past while building a relationship between us.

I think it is good for all T's to have some level of understanding of your past. I think it is fine for specific topics to never be talked about and/or your past not to be a focus of your therapy. It is your therapy and if you don't want it to be a focus on your past, then talking to your T about that desire, the why of it, and what they are hoping to get from it would be one way to deal with it.

Bottom line, you don't have to tell a T anything you don't want to. You also are the only one that knows if you need a T that pushes some or one that meets you where you are and lets you unfold at your pace.