12 -
A girl can get her period anytime between eight and 15, but on average it occurs at the age of 13.
13 -
As boys grow, their voices start to break. An essential part of puberty, it can happen anytime between 12 and 16.
15 -
A teen boy can start to develop facial hair anytime between eight and 12. However, by 15 most men have enough strands to justify their first razor.
16 -
An important year in the US for both men and women, 16 is the age they can receive their driving license. The average age in the rest of the world is 18.
17 -
Though some statistics indicate that men tend to lose their virginity a little earlier than women, the average age is 17 for both men and women.
18 -
When we officially become adults, 18 is also the age at which our brain's processing power is at its peak.
25 -
Our strength peaks around the age of 25. It plateaus through 35 or 40, and declines at an accelerating rate by the age of 65.
27 -
In the US, the average age of a first marriage for women is 27. That's a big increase from 23 in 1990 and 20 in 1960.
30 -
At 30, both men and women have the densest and strongest bones. After that, bone mass plateaus for women until menopause, when it drastically declines.
35 -
While men reportedly hit their sexual peak at 18, women do so around 35. Presumably because that's when the biological instinct to have a baby hits.