Yeah, I wrote down that Asuna is 17 and Kirito is 16 in Ep. 14's wiki page. I find it nice that the girl is older than the guy. Most people find that weird for some reason. Besides that, I have to change my caption for Sugou, and the age for adult in Japan is 18 like us in the U.S. It used to be 20 back in 2008.
Speaking of psychotic players, I don't think we'll see any. They were pretty rare, and the show is pretty mellow than Btooom! which has some messed up players who became more sadistic and violent as they play the game in the real life.
The difference between Btooom! and Sword Art Online is that in SAO, you died in the game means death to you. For Btooom!, you are forced to killed 6 or 7 (can't remember) players in order to escape from the game that is being played in real life. The issues with trust is more fragile in that series than Sword Art Online.
Dang, I got off tangent again.