When were the ages to enlist each military branch established?

So, I've been doing some research on potential career paths and one that sticks out is the military. I'm curious about the history aspect of things. Do we know when the age restrictions to enlist in the different military branches were established? Or has it always been this way?

The age eligibility for enlistment in the United States military has a long history rooted in legislation. The current age of enlistment for each respective branch varies, with the minimum age for the Navy, Army, Air Force, Coast Guard, and Marine Corps being 17 (with parental consent) or 18 without parental consent, and the maximum age usually extending into the early 30s, with some variances for each specific branch, officer candidacy, and professional roles.

The minimum age of 17 for enlistment with parental consent was established during World War II, when the Selective Training and Service Act of 1940 was enacted. This legislation required all men aged 21 to 35 to register for the draft. The age was then lowered to 18 in light of World War II needs through the Armed Forces Voluntary Recruitment Act of 1942. The signed parental consent for those under 18 was required to ensure that underage recruits understood the nature of military service.

The maximum age for enlistment varies more widely and has been adjusted over time based on the needs of the military. In periods of increased conflict or personnel shortages, the maximum enlistment age has been raised to allow more individuals to serve.

However, these ages have been modified throughout history due to world events and adjustments in overall military structure and strategy. It's also important to note that these ages for enlistment commonly apply to non-officer roles, as those aiming to become officers generally need to meet different requirements, often related to education levels and specific professional qualifications.

I should also mention that the newest branch, the Space Force, follows the same age eligibility criteria established for the Air Force since it operates underneath the Department of the Air Force. As the Space Force matures and grows, it's possible they may establish their own unique age and enlistment criteria.

Thus, while there has been a steady age requirement in place since the 1940s, nuances have been adjusted over time based on the needs and evolution of our military forces.