Jerry is described as "the young English boy" in the first line of the story, but the narrator later specifies that he is eleven years-old. He is at an age where he is still impulsive and childlike at times, still longing for his mother's approval; however, he also very much desires increased independence and freedom from his mother. We learn that his mother is intensely aware of this as she worries over his safety without her but tries to reassure herself that he's old enough to be alone. She doesn't want to smother him with her affection and attention, but she also doesn't want to give him more freedom than he can handle.
As far as his family situation, Jerry is an only child, and his mother is a widow. This likely increases his mother's concern, that she has to be both mother and father to Jerry and has no one to consult with about his development into an adult.