I've introduced a lot of people to cycling .... but they were all under 15yrs old at the time. My cut off is 16, I figure they can bounce back (bounce being the key word) when they are young ... Since it's not a matter of "IF" ... it's "WHEN".
Of course I have lots of friends who see how much I ride, what I ride, and ask ... "do you think I should get a bike?" or "I'm getting one too, what should I get" and "If I get one, will teach me to ride it?" . Over 15yrs and I just say NO ... no I don't think you should get one, no I don't know what you should get if you won't ride a Honda Rebel and no I won't even ride with you let alone teach you.
You guys know how it is .... co-workers, friends, neighbors etc want to be "like Mike" when they see you on that monster. They see a 40 or 50 something doing it and want to do it too.
My response is always, "what kind of bike do you have now?" ... Uh, I don't have one.
Well, ... "what kind did you used to have?" .... uh, I've never had one.
Then don't F-in start now!
I had a number of college friends who went out and bought a bike as soon as they were away from mommy and daddy. Most of those are dead, the others wrecked them and quit right then.
I'm brutally honest about how I feel on that subject ... If you didn't grow up on one, then don't start now! You had the body, bones and time to recover from the crash YOU ARE GOING TO HAVE when you were young ... you don't have any of that now! So no, I won't help anyone learn how to ride unless they are children, that's why I keep my mini bike around and running since I was 5yrs old. If someone insists they are going to start riding anyway, I offer them the mini bike if they want my help, and it's perfect for the little ones to learn on.