For me it was a playboy at 13, for my friends probably the same, but I'm sure the internet bring the age lower,and pack more actions.
When I think about your link of a graphic novel and the first playboy I read, I'm pretty sure any parent would prefer the graphic novel where a poorly done 2 image strip depicts a fellation, and the text besides is... Less than erotic let's say.
And btw: i read 'when I was 5 I killed myself' from Buten at around the same age (maybe 14), as well as flowers for algernon and 1984, I don't think they are age-appropriate books, but they are worth reading when adolescent, because you experience them harder, and formative.
Buten in particular wrote hard books.