The President is both the head of state and head of government of the United States of America, and Commander-in-Chief of the armed forces. Under Article II of the Constitution, the President is responsible for the execution and enforcement of the laws created by Congress.
You can join some branches of the United States military at the age of 38 years but not others. The Army, Navy, Air Force, Marine Corps and Coast Guard each has its own minimum and maximum age requirements for enlistees, including for new recruits in the active-duty ranks, the Reserves and the National Guard.
Under federal law, the oldest recruit any military branch can enlist is 42, although each service sets its own policy within that limit. Annette Crawford, a spokeswoman for the Air Force Recruiting Service at Joint Base San Antonio-Randolph, Texas, said officials would be watching to see whether the aches and pains of approaching middle age are too much for older recruits.