Replying to https://twitter.com/undefined/status/1356614308109508608:

@MatthewSpeak @GibranStormcrow @brazen_unicorn @freethinking100 @IckyVickyEww @Not_Meis @zachsilberberg When brains change over time that is just as likely to be decay as development.

Nature turns children into adults through a process called puberty. That usually ends around 14 years of age. The vast majority of 15-19 year olds are adults.