The qualifications for becoming a fighter pilot are deceptive. On the one hand, it is ridiculously easy to join our nation's armed forces. Except under special circumstances, if you're an American citizen at least 18 years of age or older (17 with parental consent) but under 35, and you've earned your high school diploma or GED, you can join the service. To become a pilot, though, you also need to be an officer, but those qualifications are only slightly more critical: being at least 19 but under 36 and having earned a four-year BS or BA degree are the main differences.
From there, things get a bit more…classified. Both the Navy and the Air Force have traditionally been pretty secretive about what exactly the "right stuff" consists of. There are several different training schools where one can learn to be an effective fighter pilot (one of them is actually called TOPGUN, no lie), but the qualifications for admittance seem to be a matter of national security. What we do know is that, if you want to be a fighter pilot, you have to be smart (to handle all the controls), determined (to handle all the tests and training), and physically fit (to handle all the g-forces), and you must exhibit that you take orders like a computer, handle pressure like a brain surgeon, and have a level of emotional and mental maturity that would stun Sigmund Freud into silence.