Have you ever been told to "grow up" in your twenties or look for an excuse to explain why you always find really fun Internet chat videos?
Well, maybe you have an official reason not to act like a mature adult.
Brain scientists believe that people do not become fully "adults" until they are 30 years old.
At the present time, the British law states that you become an adult at the age of 18 years.
Scientists studying the brain and the nervous system say that the age at which one becomes an adult is different for everyone.
Research suggests that people over the age of 18 are still undergoing brain changes that can affect behavior and make them more likely to develop mental health disorders.
Professor Peter Jones from Cambridge University said, "What we are really saying is more and more absurd about when you are going from childhood to adulthood.
"It's a much more nuanced transition that takes place over three decades."
He added, "I suppose that systems such as the education system, the health system and the legal system make it easier by providing definitions."
When you reach the age of 18, you can vote, buy alcohol, get a mortgage and be treated as an adult if you have problems with the police.
Despite this, Professor Jones said he believes that experienced criminal judges recognize the difference between a 19-year-old accused and a "hardened criminal" in their late thirties.
"I think the system fits what is hidden under our eyes, that people do not like the idea of a caterpillar that turns into a butterfly," he said. -he declares.
"There is no childhood, and then of adulthood, people are on a path, they are on a trajectory."
Professor Jones is one of many experts attending a meeting on neuroscience organized by the Academy of Medical Sciences in Oxford.
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