Little bit older, maybe a little bit more mature, but I have seen very few kids come back from a mission changed people... If they were peter priesthoods before they left, the mission will amplify that... If they were the kind who might get themselves into trouble, then they will return about the same. I just haven't seen many kids who weren't mostly the same when they came back as when they left. It happens, but in my opinion that is the exception, not the rule.