Nice idea, however there's not enough of a connection with the subject. Back of heads works sometimes, but I for this challenge, I think an emotional connection to the mother and child would have helped. Hard to get the gridiron game in if you took it from the other side, thereby eliminating the "story" in the photo, same too if you had them pose for the shot... hard, I know. Let's leave that aspect. The composition isn't bad, the use of a shallow DOF works here, as the background adds context to the story without being too much of a distraction. Not sure why you chose to go with B&W with this.
I think I would have rotated the frame just enough to level out the field, I otherwise like the composition here, taking the picture from behind the subjects also emphasizes the action of the mom covering her child's ears, without the distraction of the faces
Interesting capture. I would have liked to have seen more of the babies head. Maybe a shot from the front would have turned out better. The background is also a tad distracting. With a levels adjustment to make the black a little darker.