<p>I don’t think it’s that casting directors are hesitant to hire 18 year olds fresh out of high school because they haven’t proven they have discipline through a college program. I think it’s that it is probably a combination of things that make it hard to be cast, including the fact that there are not that many roles at all, it seems, for kids that young <em>and</em> the typical 18-year-old hasn’t the experience and training to make him able to handle most roles he might be cast in. Perhaps those are reasons why a director would choose, if given the choice, to cast an older actor (well, older than 18) who can play younger, rather than a really green and young 18-year-old. But I would question whether college had anything at all to do with it.</p>