Note here, it's sweet 16, not sweet 18, 21. Nor sweet 30, 40.
SIXTEEN. This is when, girls have just became sexual for a couple years. As to a peach that become ripe.
Also note, sweet 16 refers to females, not males. Males, is never sweet, at 16, 26, 36, or 46. Males, are sweet when there's money and power.
for lyrics, see: http://xahlee.org/music/sweet_sixteen.html.