I don't disagree --but I don't want to overreach. It's bad enough kids are graduating not knowing the perils of compound interest. Yes, it would definitely be better if we started earlier, but let's go for the easier goal first.
Younger kids could yield better results since they tend to take interest in adult stuff and will likely pay more attention than a teenager.
It is very easy to play a game with debt and interest.
The earlier you start the more time to have to grasp the concept eventually