Well, as you know, it's all guesswork however I think Occam's Razor would suggest that the perp is someone older than 25. I think that by discounting what we know about the perp--that he is disciplined, thinks ahead and plans--all traits of older people--and replacing this with a theory that the influence of electronic games/Hollywood could override the natural impulses, lack of experience and foresight that very young adults exhibit is unfounded speculation. JMO. That said, you could very well be right--we just don't know much about this Sicko.
You could very well be right too. Hopefully we won't need to speculate much longer...