Welcome to the forum

There are a few of us that have this book as well and I think we all enjoy the candid opportunity shots that photographing children presents.
You've got a nice photo there - good depth of field, nice contrasts for the black and white too. About the only comment that I would make is that it seems to me there might be a bit too much background in the photo. It might be interesting to see what it would look like if some of the background on the left was cropped off.
Cheers,
Malcolm