I'd like to see whether in fact it's true that habits are entrenched by the age of 16 and therefore that it's just extra to go beyond the age of 16. From what I can tell with young people, I think they're just at a formative stage at that age and that anything you can do to keep ingraining into them certain habits and regimes and regimented activity, the better.
Unless hearing otherwise, I'd be inclined to support the extension to 18.