Not just years, but I think it would take decades or even a century. The older people don't know how to use the Internet, or at least unable to do so. There are people in their 40s or 50s that still don't want to embrace technology since they grew up without it. It's only the incoming generation that are so well-versed about the technology. Kids of today have iPhones and all that techy stuff so bitcoin adoption might start from them but we can't really assure that
Some twenty years ago kids had personal computers where you had to install an operating system as well as properly organize your working environment all by yourself. Today's iPhones and all other techy stuff comes with almost everything preinstalled already, and if you want something else you just search for it in Google Play and Apple Store (or how it is called) and then click-click-click. Honestly, I don't think that the kids that you refer to will be any smarter than the adults as of today...
We can only hope that they won't in fact be dumber with all their useless stuff sending selfies to Instagram