Is there someone under 18 actively using Bitcoin? Could you describe your experience? Have you ever faced age restrictions using it like there are with the real world money? For those are over 18 perhaps you have some younger friends stories?
I'm 18 now but I used it while under 18. I faced no restriction. It was actually extremely helpful to me since I needed to buy some domains and hosting and credit cards, even pre paid ones, are illegal in my country for those under the age of 18. So, my experience was quite the opposite: I faced less restriction by using Bitcoin.
With regard to kids under 18 using Bitcoin, here's one example http://milkroad.org/