Jerry's primary concern is to be accepted by the boys, as he thinks:
"To be with them, of them, was a craving that filled his whole body."
This may be due to the seeming fact that Jerry does not appear to have many friends. He does not speak of any friends back home, and his mother's overprotectiveness may also be a contributing factor to his desire to be one of these seemingly free and independent boys. The author demonstrates the mother's worry over her son by stating:
"She frowned, conscientiously worrying over what amusements he might seretly be longing for, which she had been too busy r too careless to imagine."
Slightly further down in the introduction, we once again are privy to her thoughts:
"She was thinking, Of course he's old enough to be safe without me. Have I been keeping him too close? He mustn't feel he ought to be with me. I must be careful."
This shows the likelihood that up until now, Jerry has been quite guarded by his mother, and thus lends to the idea that he probably has few friends, increasing his need to be accepted by the boys.