@Shamar I usually do 14-18 year olds.
For younger kids, I start with something that intrigues them - like the fact that in Poland they >can< download a movie from the Internet as long as they don't share. Once I have them hooked, I continue to "harder" topics.
I'm trying not to scare them too much, and for every threat I show them a way to deal with it. It doesn't need to be perfect - if the install Privacy Badger, they are SAFER and they shouldn't obsess about fingerprinting.