They have no idea whether they'd be happier doing something else. I quit college in the middle of my junior year and enrolled as a student at The University of Planet Earth. It has billions of professors, tens of millions of books, and unlimited course offerings. Tuition is free. There are no degrees and no one ever graduates.
Students pose their own questions and design their own curriculum.
Every Sunday, attend a different place of worship. Seek out hundreds of role models and mentors. Create my own personal bible, almanac and telephone book. For discipline, live in high-crime neighborhoods. That ought to keep a gun to my head.