I’ve never heard of that legal distinction, but I want you to go talk to any parent of a 13 year old and ask how they refer to a 13 year old and the vast majority will call those people a child and also call them a teenager. A ton of teachers will do the same thing.

At age 19 you are still a teenager but in the eyes of the law many times you are considered an adult.

So it is fair to call a 13 year old a child because basically they still are.