The Oxford English Dictionary defines middle age as 45-65, but midlife crises are affecting more people outside of that age range—both younger and older. In Silicon Valley, Hollywood, Madison Avenue, or any company that is trying to compete in the digital economy, people have begun to start feeling old in their mid 30s. And, with our additional longevity, more of us are ignoring the traditional retirement age and continuing to work until our mid 70s or beyond.
https://greatergood.berkeley.edu/article/item/how_to_overcome_the_struggles_of_midlife