I'm 29. A friend I work with is 29. My aunt is 36. My sister is 26. My cousin is 31.I know it depends on where you're from and how old you are but I only know 1 person over the age of 20 with an iPhone. Everyone else I know and want to message ha a blackberry.
These are just a few of the people I know with iPhones, ranging from the first generation (mine) up through 3GS.
I know not a single person (that I know of) with a Blackberry of any type.