Unexperienced

"Jimmy Cross did not want the responsibility of leading these men. He had never wanted it. In his sophomore year at Mount Sebastian College he had signed up for the Reserve Officer Training Corps without much thought. An automatic thing: because his friends had joined, and because it was worth a few credits, and because it seemed preferable to letting the draft take him. He was unprepared. Twenty-four years old and his heart wasn't in it." Page 160 and 161

I was shocked by one thing in this passage. Jimmy Cross was twenty-four. A twenty-four year old was in charge of an entire platoon of men. He had no experience and no military ambition. He had this huge responsibility on his shoulders. This responsibility that he had never wanted. He was just as naive as the rest of them. He didn't think he was worthy of this job and neither did his men. So, how did he end up in charge?