Ah, impressive animation, though the dick looks strange.
As for xamend's question, that is because even though the age of consent is 16 in most states, adults 18 and over still can't have sex by "so-called law" with them legally which makes no sense. Teenagers are still going to have sex with each other regardless of age of consent laws though, so they might as well say outright it's 18 across the board, but then again these laws are created by old people and reactionary types who are out of touch with today's world. You should already know consider how touchy everyone is with this these days as it is.
It's a lot like Japanese age of consent laws were it's at 13, anyone 18 and over can forget about it for the most part!