I'll be 39 next month. Practically a fossil.
My 13yo and 16yo kids will not be getting iPhones. I plan to keep my current phone activated for them to borrow if they need a phone, but they won't be getting their own phones for a while. I teach HS, and I see way too many kids texting surreptitiously when they should be doing their work.
It absolutely floors me that 16-25 is the most represented iphone-owning age group. But, I think its less indicative of the demographic that owns an iPhone and more of which age group spends time on an iPhone forum...