The Birkin belongs to Carlyne Cerf de Dudzeele but that's not her - I'm guessing she styled the photo. It's a B35.
You guys are really knowledgeable. I just googled Carlyne Cerf de Dudzeele; found another photo of this bag. This worn-in B is just so beautiful
http://iloveyourstyle.com/snapshot-best-birkin-bag-ive-seen/