Jim's background

This may have been discussed previously, and if so, I apologize for a potentially redundant question. If so, please kindly point me to the relevant topic.

If not, though, then here's my question: Jim seemed to hail from a relatively middle-class family, judging by the suburban house, which seemed quite comfortably set, as well as the family dynamic shown from the tape he was watching. Still, he was, at an age of over 20 (I assume from looks and social skills), working as a bicycle courier, which, with all due respect, appears as a job for a person of lesser age or a more modest background.

Unless I'm wrong about the social and financial benefits of bicycle couriers in the UK or about placing Jim's age at at least 23 or 24, then it is not logical for him to be doing it as a job.

Any ideas on what the case may be? Going to uni and doing it part-time may be one idea, but still?