Time to Grow Up: Scientists Say We Don't Become Adults Until Our 30s

If you’ve ever looked back on some of the questionable choices you made during your 20s, now you have a legitimate excuse for those poor decisions. From bad haircuts, partners you would soon like to forget and behavior that makes you cringe — it was all because you simply weren’t an adult yet, and now you have science coming to your defense.

While we usually attribute adulthood to the ripe old age of 18, scientists in the U.K., who study the brain and nervous system, say the age at which you become an adult is different for everyone, and it isn’t until we are in our 30s that our brains fully mature.

When you blow out the candles on birthday number 18, you might be stoked about adulthood, but scientists say our brains are still changing well into our 20s. Additionally, there is no strict neurological definition of when a child becomes an adult.

Our brains continue to change, and therefore, we continue to change. These changes can affect your behavior, personality and your overall mental health. In correlation, scientist also noted that people are highly susceptible to mental health problems in their 20s.

"What we're really saying is that, to have a definition of when you move from childhood to adulthood looks increasingly absurd,” Professor Peter Jones of Cambridge University told BBC News. "It's a much more nuanced transition that takes place over three decades.”

While everyone’s brain seems to reach adulthood at different ages, Jones explained that we are legal adults once we become 18, and this fact is really out of convenience rather than a sense of order.

“I guess systems, like the education system, the health system and the legal system, make it convenient for themselves by having definitions," Jones said.

So, when those Facebook memories from many moons ago pop up and you feel cringy about a picture or something you posted, simply say, “Meh, I was just a kid back then.”