It looks very nice but his chin and the shadow beneath it are cast wrong if you are basing it directly on that picture. Notice that the butt of his chin starts slightly to the right of the left tip of his lips and the shadow being cast under his chin on his neck is perhaps 10-15 degrees to the right of direct downwards from his chin. You have started the butt of his chin slightly further left of the left tip of his lips and cast your shadow at about 35-40 degrees to the left of direct downwards. These two changes make his face more angular and change the lighting pretty dramatically (moving it from where it is in the background to more like a little infront of him and high right.

Either way, it's very nice in grey already and I look forward to your progress.

Great job and good luck!