
Why was 18 chosen as the age to become an adult?
"Originally, the ‘universal age of an adult’ was 21. This is because at 21, a squire would be sworn in as a knight. However, during WWI, there were so many deaths that the draft age of 21 was lowered to 18 and it just sort of stuck that way."
Many of the answers are just made up and are really not correct: #2, #4, #6, #11.