well any later and they'd have left home
and to do that, you need a job. At 18 you are most likely still living at home, so can drop it all and go to University.
( spangolin - the odds are good but the goods are odd, Wed 26 May 2010, 22:46, archived)

It would sort out the ones who really give a toss, and no mistake.

( Moon Girl Technologies horrendous beanbag, Wed 26 May 2010, 22:50, archived)

you'd be left with the ones with rich parents, surely

( spangolin - the odds are good but the goods are odd, Wed 26 May 2010, 22:52, archived)

...and the ones who give a toss.
Mature students DO exist.
( Moon Girl Technologies horrendous beanbag, Wed 26 May 2010, 22:54, archived)