A person's brain does not really mature until around the age of 25. Explaining why so many of our young people do the stupid things they do.

Lest we forget a former UH volleyball player, Tony Ching, 21 YO who rode his moped without a helmet. Crashed and almost died. This is not a lesson learned. 

http://archives.starbulletin.com/2003/05/24/news/story2.html