I'm going to dive in here with what is perhaps a different angle to this. People are talking about laws and punishment and other logical approaches. I'd like to speak as a woman, who was a girl of 14 (and all the other ages we've talked about of course).
At 14, sex is something talked about in school sex ed classes. Its usually mentioned as an aside to birth control and mentruation discussions. Details are often slim. Never mind talk of love, learning to respect one's own wishes and boundaries when pressured by boys and/or men, or how easy it is to get hurt. For many 14 year olds sex is both titilated and frightening. "They're going to put THAT into THIS? Are you f-ing kidding me???" The fear. The giggles. The confusion. Let us not forget that sex for a girl/woman is sometimes very difficult or painful the first time. Breaking the hyman. Dealing with physical pain and blood. Dealing with shyness or uncertainty. And somehow, with all the "white knight" rescue stories out there, far too many girls are prepped with romantic ideas of love instead of practical matters like emotions and the differences between many boys who just want sex vs. many girls who just want love. How many girls mistake sex for love? How many girls say yes when they really aren't yet sure because of peer pressure?
These are questions that a 30 year old man is not equipped to answer.
What IS the answer? I want for every girl to have massively more detailed sex education. I want every boy to have massively more detailed sex education. And ALL of these issues need to be addressed to help avoid a lot of misunderstandings. I know far too many women who have never even experienced an orgasm. Why? Because they were hurt along the way, pressured into things they didn't understand, and never really learned about sex as making love. As a sharing between equals. It's sad. Very, very sad.
When I read these notes about this topic I can't help but cringe inside. Reducing a girl's experience to logic or laws or rationalizations is to miss the point. Those are all simply ways of saying, "we don't want our children harmed, and in today's society, with sex still so stigmatized (virgin/whore, for instance), this is the only way we know how to do it."