If you are someone who finds the multi-pronged genius of Bo Burnham gallingly unjust, then brace yourself. The comedian has turned to film-making, and nailed it on his first go. Burnham has spoken about his own anxiety issues, and Eighth Grade beams us directly into the headspace of maybe the most anxious species on the planet: an introverted 13 year old girl who doesn’t know how to be cool. Kayla (the unforgettable Elsie Fisher) is a sweet, awkward kid about to finish the titular class year and head into the dizzying young adulthood of high school. At school she has…