Fortunately you can easily change it. If you go to https://appleid.apple.com and login using their account details, in the Password and Security section, you can change the year of their birth. 1/1/2001 works fine, I think the key is that they need to be over 13 to change from Adult to Child account.
Benjy Fenwick (d. 1981) was a wizard and member of the original Order of the Phoenix. He fought in the First Wizarding War and was murdered and mutilated by Death Eaters before the war's end.
Head of House. Filius Flitwick is the Head of Ravenclaw House. He is the Charms professor at Hogwarts and the most knowledgable Charms master alive today. According to the Pottermore welcome letter, when Ravenclaws are extremely upset he makes little cupcakes do a dance to cheer them up.