A separate comment to explain a little more. In my country having sex with a person younger than 13 is considered rape, even with consent. If the 13th birthday is today, is it right to do it today and not yesterday? Why?

If a barman sells tobacco to someone who's just turned 16 it's legal. Why wasn't it legal yesterday? Laws need this kind of hard limits. Abortion is legal in many countries within certain weeks of conception. Abortion is illegal (but not murder!!) simply before birth. Penalties are different, that's the law.

I'm very happy to have laws, even if I don't like all of them, because they're way better than someone's sense of morality.