I was already a teenager when it started and that has pretty much the same effect IMHO :3. The funny thing is all of us in high school never thought of it as a show for little kids at all, even though the PPG were five. Their ages were like a footnote to how happy and dark the show was at the same time...
I still have a hard time thinking of it as a show for little kids, not even with the 'adult' jokes put into account (most of which I and my friends as less hardcore fans never thought of anyway) for some reason....