A midlife crisis doesn't have to happen during middle age. You're coping with midlife crisis whenever you're agonizing over, "What have I done with my life?", "Why haven't I done more with my life", "What should I be doing with my life" or any of an almost countless number of variations on these questions. This happens to almost all men and women. Often more than once.
The point is - you're not happy with yourself or your circumstance or both and you're unhappiness has reached a point where you feel compelled to do something about it. Good or bad. Smart or Stupid. Forgiveable or unforgiveable.