First let me say that I really love this portrait. I want a portrait to convey what is human about the subject and I see so much in her face. We all construct a guess about a person when we see a face and a photographer's job is to give us a view with not just enough information to construct a good guess, but a view which compels us to do so. You have done all of that.
I must say though, that the first thing I saw when I looked at this image was the straight, strong vertical line made by the viewer's right edge of her light colored scarf contrasting with the dark gray of the background. The line is so strong as to be almost startling. I tried to crop the dark gray closer and decided I liked it better your way. I imagine that when you shot it you gave thought to the text of a magazine article or whatever filling that space. If so it will be an odd sized page.
Anyway after looking at the image for a long time I think I like her face more and more. I still find the strong line/division of the image slightly distracting but I want to see the image in its final use whether in a gallery as a print or in print with the article reversed out of the right side. Nice work.
John, thank you for the thoughtful input. You are giving me too much credit in planning that line. It was unintentional. This image is an ongoing hobby of meeting, and photographing, strangers.