The US military takes enlistees at 17 and a half years old. Usually from poor families.

I believe the US lets people enlist at 17 (with parental consent) but they don't deploy them to combat before they're 18.

I encourage you to you watch this movie, btw.

And see also:

• https://en.wikipedia.org/wiki/Resistance_Inside_the_Army
• https://en.wikipedia.org/wiki/List_of_Iraq_War_resisters