My T is aware of my past, but I am not sure if I have ever verbalised it. She read my writing, a letter to someone else that I had written but not sent, because they weren't here anymore.

Since then, it has been acknowledged in a couple of sessions, but never actually spoken about. A T shouldn't pushz in my opinion. You need to be ready.

My Old T did push, and it sent me into a huge dissociation in session. I disappeared right on into that black hole of nothingness. Not helpful, really, but I do understand and accept her reasons for doing it. (Too long and boring for here probably).

If you aren't ready, you run the risk of damaging the relationship between you, too, which wouldn't be a good thing, in my opinion, as well as sending you into a tailspin.

If you don't feel ready, then you probably aren't. Trust yourself, and tell your T you don't want to discuss it yet. Little by little. Slowly and gently. Maybe just acknowledging its existence is enough, for now.