I’m on facebook and there are a few pages dedicated to Vietnam vets and/or troops who were KIA. One of them was a 14-yr-old Marine. He fell in the line of duty.
How on earth can a 14-year-old fight in a war?
That was very common during the American Civil War.
Not wanting to actually lie, they would put a piece of paper inside their shoe with the number 17.
When asked by an office, "How old are you." they could truthfully say, I am over 17.