I don't even understand the point of this. Either you're too young to even understand what porn is, or you're old enough to view it. There is, to me, no age where a minor is old enough to desire pornographic content but not old enough to not be scarred by it.
What are teenagers, a demographic with an insatiable appetite for sexual gratification, even supposed to do? My grandpa was probably wanking it to a Macy's catalogue as a teenager. Denying or trying to suppress it is not gonna have the outcomes people want.