But it's not just interest, it's ability to complete the course. Sure I might be interested in Mathematics, but terrible at it. What's the point of admitting me to an Honours Maths cousre? Also, there are usually strict legal limits on the hours you can work if you're under 16, which is when you'd be studying for the exams required for University admission, so I don't think it'd be much of an issue. Note that I'm thinking of the UK, where University admission is usually at 17 or 18.