It used to be—at least in the last 50 years—that transitioning to adulthood was fairly straightforward: You graduated from high school or college. You found a job. You got married and started having kids. Today, many 20-somethings aren’t necessarily hitting those traditional markers of adulthood until much later in their lives, if they hit them at all. Some live with their parents until their late 20s.

There’s no question the hard line between childhood and adulthood is blurring, but some experts insist that historically this period of emerging adulthood in the early 20s is actually pretty normal.

“Except for the brief period following World War II, it was unusual for the young to achieve the markers of full adult status before their mid- or late-twenties,” writes Steven Mintz, author of The Prime of Life. (The Atlantic)