Not exactly an AIBU, but
How do you know?
My DS (19) is really struggling with this at the moment. He's working in a fairly well paid P/T role at present so he's earning about £400 a week before tax, but it's all evening and weekends, and its not a career - he's been there nearly a year and most people are newer than him.
He's got A levels but didn't want to go to uni.
When in 6th form he thought about teaching but did some practice in a local primary and hated it. So that was out. He has thought about accountancy as He did a related subject for A level but a friend is doing it at uni and from what he's heard DS doesn't want to do that either. He has no interest in IT or anything (the route his younger brother is set to go down), is no good at anything practical, like me he is a leftie, quite clumsy and not good at practical tasks. His main interests are football and watching idiots on YouTube, neither of which lend themselves to careers 
I knew what I wanted to do when I was 14 so I don't know how to help him...What can he do? How can he work out what will interest him? He's also got used to a good salary now so I know will be reluctant to give that up for something paying less...!