How come there are 18 year old soldiers but no 18 year old cops
The Pentagon is concerned that the pool of qualified young people to recruit from is shrinking [5]. About 75 percent of America's 17- to 24-year-olds were ineligible for military service due to lack of education, obesity, and other physical problems, or criminal history in 2009 [1, 2, 3]. About 27 percent of young Americans are simply too overweight to join the military [3]. Roughly 15,000 young potential recruits fail their entrance physicals every year because they are too heavy [3]. Additionally, about 30 percent of those who do have a high school diploma fail the Armed Forces Qualification Test, the entrance test required to join the US military [2]. One in four young people between 17 and 24 does not have a high school diploma, and an additional one in ten young people cannot serve because of past convictions for felonies or serious misdemeanors [2].
There are no hard and fast rules about the minimum age for police officers, hence why some police departments have no upper age limit [3]. However, most departments do have rules about the maximum age for new applications to begin training and to be hired [3]. The age of 18 is generally considered too young to be a police officer [2][4] due to the amount of maturity and life experience required [2][4]. Army soldiers, on the other hand, do not generally have the same level of maturity and life experience as 18 year old police officers [2][4]. This is because being a soldier is a closed and controlled environment and soldiers have specific responsibilities [1][2]. Police officers are on their own after approximately 8-9 months of training [1][2].