PEN15, the middle-school-set Hulu comedy, manages to pull off a strange casting magic trick with remarkable aplomb. Its creator-stars Maya Erskine and Anna Konkle, whom are adult women, play themselves at age 13 among a cast full of actual 13-year-olds — and they blend in perfectly. It results in a downright magical-feeling show, a gentle, earnest, very awkward comedy that will remind everyone what it feels like to be in the most horrific years of your life. Season 2 is coming September 18, and the first trailer gives us everything I loved about season 1 …