I think that if you really are BPD and your T doesn't want to work with BPD, she would have sniffed this out during session 2 or 3. I don't think it takes that long for those tendencies to emerge.

I think a lot of the criteria for many of the personality disorders apply to lots of people. I think having the disorder per se is more about the severity of the symptoms and the overall damage that the disorder does in one's life.

But my advice, of course, is to ask your T about it. I once thought I had a particular diagnosis, and talking to T about it was a really useful way to get feedback about how he saw me. And how distorted I can perceive others' reactions to me. So it's a good conversation to have, IME.