You know what one of the great things about therapy is? Even though you said you would tell her about your first sexual abuse memory next time, you do NOT have to! There probably is way more pressure in your head to do it, then from her. She seems to understand you and get where you are coming from, and I bet if you aren't ready to talk about it next session, or in the next 6 months, she'll be ok with that. I've never experienced any SA, but my T has told me time and again that it is ok if I don't want to talk about something right then, even if I am struggling to try. She knows it takes time, and as she put it a "big leap of faith"