Category: Milestones

Scientific research indicates that the human brain, particularly the prefrontal cortex, continues its development until around age 25. This makes the transition into the period that follows, often referred to as later young adulthood or simply adulthood, a significant milestone and a key part of understanding **what is the age after 25 called?**.

According to the World Health Organization, adolescence technically ends at age 19, yet experts in developmental psychology suggest the transition to full adulthood can last well into the mid-twenties. This creates a surprising and complex answer to the question: Are 21 year olds still teenagers? The reality is a blend of legal status, biology, and social expectations, with scientific evidence revealing a more nuanced truth than a simple calendar age might suggest.