When You'll Know You're Middle Aged The concept of middle age has become increasingly ambiguous, with its definition shifting over time.
Psychologist Margie Lachman, who has spent years studying midlife at Brandeis University, notes that people's perceptions of middle age vary greatly depending on their current age.
The older you are, the later you tend to think middle age starts and ends. This fluidity reflects broader societal trends. In a youth obsessed culture, people want to cling to their youth for as long as possible.