Age of consent is pretty much arbitrary. I think in Japan it's 13 while in the UK or some parts of Europe it's 16. It's a subject about when do we consider a human "mature".
If we define maturity through brain development (neuroscience/psychiatry), we don't mature until the age of 25. In psychology, you'd have to undergo tests to help identify if you're capable of making decisions on your own without outside influence (because children are impressionable, easily influenced, and therefore "immature").
Historically speaking, the idea behind "age of consent" in some religious conservative societies is the idea that once a girl has her first period, she's ready to bear children. She's "ready to be ploughed for seeding" so to speak. If her body's capable of becoming a mother--signaled by first menstruation--then she's capable of sexual relations, regardless of whether she's a pre-teen or older. Some girls have their first period at age 10. Now that's just insane, right?
While I disagree to 12-13-14 as age of consent, I wouldn't wanna raise it absurdly to 18-25.
Late-teens (16-17-18-19) should be able to safely sexually experiment with each other, or with an adult with whom they have ample evidence that they could be safe with. So I think, the safest we can agree on is across the board raise the age of consent to 16. That's it. Below 16 is automatic statutory rape regardless of who has sex with whom.