If I had a dollar for every time I saw a "I didn't get my letter from Hogwarts" joke, I'd probably have as much money as JK Rowling, who apparently now has the luxury of spending her days responding to fans on Twitter.
The author's latest entry into the JK Rowling Twitter Hall of Fame (seriously, she's basically the president of the great nation of Twitter at this point) reminds you that even if your letter didn't arrive by owl, you definitely went to Hogwarts. So wipe those tears from your eyes and let the books be your Hogwarts Express.