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.
-- Fenrir Greyback Fenrir Greyback was a werewolf, low-level Death Eater, and friend of the Malfoy family. He killed for fun and especially enjoyed infecting children.