Remember that girl from HS that was hot as fuck? Well, she's still hot as fuck today. Tip my hat to her.
At 21 she's hotter. In fact, many of the plain, not-so-hot chicks are smoking hot at 21.
At 26 there's a 75% chance she's still hot.
At 31 many are starting to look worn - less than 50% chance she's still hot.
At 36 she's been married, now has two kids - 33% chance of residual hotness.
At 41 she's got teenage kids who are hammering her ... hotness probability less than 20%.
At 46, they have kids in college and they're just plain wrung-out. Less than 1 in 10 of the high school hotties are still anything that could be considered hot.