So I am a nonbinary person who was assigned female at birth. The thing is no one knows that I am non-binary. I came out to my therapist to as gay and it is true that I'm attracted to girls. While she was very accepting of my sexuality, I'm worried that she won't understand my gender identity. How do I come out to her again as nonbinary?
If she is professional, you should be able to just state it rather plainly. It is her job to help you, with being who you are. Though I understand your hesitation, because it took me a while before I told my therapist I was bisexual. In the end I reminded myself, I am paying this person to help me. And they can't help if I don't tell them.