Hmm... I sometimes talk to sixth-formers about academic careers (which admittedly I've only experienced at second-hand)! I tell them up-front that things are pretty ropy unless you get to the moderately senior levels, normally in your mid-30s; but I then point out that the same thing is true about most other professions, and that in academia you (generally) have a lot more freedom to do what interests you, and much more flexible working conditions than in other jobs.