One question that children are often asked is, "What do you want to be when you grow up?" This really means, what employment they would like. This question needs an answer, definitely by the time one must look for work, so at the end of college, or high school, or when one stops high school and starts working, as some 16 year-olds do in the US.
But to have the answer at those points, one must have been working on it before then, to get the necessary experiences and schooling. So at what age should a kid be able to give a firm answer as to their chosen employment goal? Of course we are all expected to have several 'careers' in our long lifetimes now, so the answer does not need to be set and unchangeable, but it has to be there in time to get the ball rolling. As the old joke goes, "Until you make up your mind, you can't change it." I have heard of many people idling around in college with no path forward. This is a disaster. They need to be desirous of something long before that. Age thirteen? Ten? When?