You’re not an adult at 18. Or 21. Or even 25. At least not according to science.
Scientists now argue that calling anyone a “fully formed adult” before 30 is more social myth than biological fact. Why? The prefrontal cortex — the part of your brain responsible for decision-making, long-term planning and not texting your ex — doesn’t fully develop until your late 20s or early 30s.
“To have a definition of when you move from childhood to adulthood looks increasingly absurd,” said Cambridge neuroscientist Peter Jones. “It’s a much more nuanced transition that takes place over three decades.”
In other words, if your 20s feel more like an extended beta test than the real game, that’s because — neurologically speaking — they are.
But it’s not just your brain that’s still loading. Society has quietly started pushing back the start line of adulthood. The average age for first marriages in the U.S. is now 30.2 for men and 28.6 for women. Birth rates for people in their 20s are at historic lows, while first-time parenthood is shifting further into the 30s.
And financial independence? Also delayed. Only 32% of 18-year-olds manage most or all of their finances without help. By 26, nearly half still rely on their parents for support. According to The Atlantic, the old script — graduate, move out, get a job, start a family — isn’t just outdated. It’s incompatible with modern economics.
It’s also incompatible with how people feel.
“Even people with jobs, families and mortgages can feel like they’re just pretending,” wrote psychologist Seth Gillihan in Psychology Today.
That sense of emotional limbo is so common that researchers now use the term “emerging adulthood” to describe the blurry, formative period from age 18 to 29. Some argue it should extend to 34.
This isn’t about failing to grow up — it’s about redefining what growing up even means. Because in a world where career paths zigzag, relationships are fluid and everything’s expensive, it’s no longer realistic to expect a fully formed adult by 22.
So if you’re still figuring it out, still starting over, still becoming who you’re meant to be — congrats. You’re not broken. You’re just evolving on schedule.
Let your brain finish booting up. You’ve got time.
