Here's how it goes (slighly tongue in cheek):
Age 10: Everything revolves around Nintendo and Football. "Big School" is a year away, which is an eternity.
Age 15: Everything revolves around "hanging out" with mates, doing all the things that seem glamourous despite the fact that they're illegal for another one to three years (which is an eternity) and of course girls - preferably just like the ones in certain magazines in their early twenties which is frankly a whole half a lifetime's age difference. Girls your own age aren't interested in you as they're all seeing guys in their late teens.
Age 18: Everything revolves around going out and enjoying all the things that you're now legally allowed to do. Girls in their early twenties see you as "too immature" and aren't interested in you. The only ones that are are annoying 15 year olds. Your physique is strangely unaffected by regular kebabs and beer.
Age 25: You're now bored with all the things you've been legally allowed to do since you were 18. Maintaining your 18 year old phsyique requires frequent visits to the gym. The realisation that you're now older than the girls in Playboy is something of a shock. Still, cheaper car insurance is a bonus. Your life still revolves around girls, but desireable single ones are getting scarcer.
Age 30: Maintaining your 25 year old physique requires daily exercise and a low fat diet. Your life revolves around mortgages, family and a career. You still find girls in their early twenties attractive, but you're now too old for them, being another half their age older again (which is frankly an eternity).
Age 35: You're halfway toward retirement age (which is frankly no longer an eternity). Your ideal car has five doors and a dog guard.
