I think trust is far from an all or nothing thing. I would say I don't trust anyone, but actually that's not true. I trust my partner not to purposely hurt me. I trust some of my friends not to breach my confidence, I trust my employer to pay me at the end of the month and I trust my manager to be honest about my work for her. All different kinds and levels of trust, but I know my tendency is not to trust.
In therapy terms, trust has been a slow, evolving concept and I would say that I trust my T to be accepting and caring of me, I trust her to be honest with me and I trust that she will always do her best for me. There are still things I struggle to trust her with and I test out the relationship much more and more often than I like but we both just accept that testing things out is part of my process with her.
Trust has grown though, it didn't start out that way at all - I wonder if it's worth looking at how your relationship with her has changed over the time, whether you can see a difference from your first session to where you are now. You may see that trust as little bit by little bit grown. I regularly think I'm more screwed up than my T does, and part of trusting her is accepting that she sees me very differently from the way I see myself. I'd love one day to see me the way she does but we aren't there yet.