How was this possible? In fact, this is only one of the most recent examples of a practice going back to the early 19th century
Aside from needing to be over 18 to sell certain products (e.g. alcohol) – your age shouldn’t affect your ability to do a job effectively.
Cutting off one’s hair is a common motif found throughout Japanese dramas, especially in anime. The action is unmistakably a symbol of deciding to change