The final Harry Potter novel was full of grand battles and grander revelations, but it also featured a tiny detail that radically changed the saga’s timeline. Although J.K. Rowling’s first book in the beloved series was published in 1997 and the final book in 2007, a date on a gravestone revealed that the events of the final novel take place in 1997. That means that Harry Potter himself was born in 1980. Which means that he’s 35 in 2015. And according to Rowling herself, that makes today, September 1, 2015, the first day of school at Hogwarts for Harry’s eldest son.