What’s the Average Age of an Actor Who Plays a High School Student?

I watch Pretty Little Liars.  It's a guilty pleasure based on a series of books no one my age should even be remotely interested in.  But a friend-of-a-friend wrote the books, so I feel obligated to watch.  That, and since I'm so invested in it, I can't stop now.  The story is getting too good!

I do know, though, that the lead characters, all allegedly in high school, not only sport $500-minimum outfits and $300-minimum bags in the episodes, but the actors are ridiculously older than 15 or 16.

Trust me, PLL isn't the only show to do this.  Check out this list of the average age of actors playing students and movies.  It's basically between 21 and 22.

The youngest?  Corey Haim was 14 when he did 1986's Lucas...which was actually age-appropriate.

The oldest?  This blew my mind, and good for her:  Stockard Channing was 34 when she did Grease in 1978.

This graphic lays it out nicely: