Good expression you've captured. A little tiny bit of catchlight cloned onto the lower eyeball would probably make this shot look a bit better, but I would not go overboard on the size of the pasted-in catchlight, or it will look faked to the visually sophisticated viewer. The overall contrast of the image looks roughly like traditional fine-grain B&W film would look, so the monochrome conversion is a success on that level.
Although many might not agree, I think the composition is a tad bit "tense" ,and although it's not generally traditional, this is the kind of shot where cropping a little bit more off the left side, maybe even into the top of the baby's head, would give a better overall, total balance to the shot, with the baby's line of gaze factored in.
I just held up my cropping L's on my big monitor...I think cropping well into the baby's hairline, almost down to the bottom of the hair on the forehead, is also a viable, worthwhile alternate crop on this shot. Might be worth a look or two to see what you think about it cropped a couple different ways.
YMMV. Best to You,
Derrel