What Is the Difference Between Teen and Adult Brains?

Teens are often characterized as angsty, impulsive, socially inept citizens without fully formed brains, straddling the worlds of being a child and an adult but how much of that is true? 

Adolescent development is categorized by the onset of puberty and ends when we choose our adult identity and behavior. The ages that this happens has changed over time; it had been suggested that adolescent occurs between 10-19 years old, but new research suggests that the upper limit is actually 24. The shift is due to the fact that our bodies are still changing into our 20’s, and our brains don’t fully develop until our mid 20’s. But what does it even mean to be an adult? And what changes are actually happening in the brain during these years of development?