I'm glad you were able to go to your first session and that it went well. I think it's pretty common to skim over things at first. The trust and comfort of talking to a t is built over time. We have to feel safe enough to go to the deeper stuff before we can actually do it. Go easy on yourself. T's don't expect the full details right away. They know it takes trust to get to the deeper stuff... if it helps, you can tell your t that there are other things you are not yet comfortable talking about. I actually just acknowledged that with my new t last week. She had asked me to talk about something, and I gave a very general overview. The next session I was able to come back and tell her there was other stuff that was left out, but I wasn't sure how to talk about it yet. She said ok and we moved on.
Hope your t experience continues to go well for you, even if it takes time opening up.