Is this one of the new ones that you haven't met yet? If so, I might hold off for a little bit, just because you won't know yet if he's trustworthy and good at his job until after you meet him and have time to consider how you feel about him. I do think sharing longer pieces of writing can be helpful, and I have done it myself a few times. My T has said that sometimes the things I write help her understand what I'm feeling in a deeper way.