Actually, I learned in my psychology class the brain goes through multiple major maturation from birth, not limiting to adolescence but into adulthood as well. The prefrontal cortex is most known to aid in cognitive maturation but not the only factor.

Fun fact: Your brain is the least organ to be damaged in extreme situations such as malnutrition; if you were severely malnourished, all organs would shut down and deteriorate before your brain does; you have a lining wrapped around your brain to protect itself from damage.

Also, on a non-psychology note, most moody teenagers are known to suffer from spells from being isolated shut-ins. It's what you do in that isolation that counts. :P