>> but just about 18 people usually start earning.

Have you seen many such people? Or are you talking about those who advertise at the subway or the pizza carrier? They earn money, for a trip, and for a cafe-cinema a couple of times a month. It was in the summer before the school started. At 18 people usually enter universities, well if on a budget, get 1k scholarships and try not to fly out, in order to at least live in the community and have more chances for a good job. Work starts closer to 21-22, in senior courses. And so is it after 25, when you accumulate formal experience, real experience and the ability to sell yourself for normal money. If you are lucky.