it's 16 in most us states, is 15 to 16 such a major difference?
devils advocate here ? 14 is young enough to be tried as an adult, shouldn't it be old enough to decide if you wanna fuck
No. That's not how it works.
For one thing, "deciding to fuck" and deciding to, say, kill someone... do you want me to continue? They don't compare in any way and I'm sure you know that.
More than anything, we want to protect kids from predators who make an entire existence out of convincing them to give it up. Predators who move through life actually looking for kids from broken homes, etc., and/or damaged kids who are vulnerable to being misguided and used.
As to "why 16, if not 15 or 14 or 12?", the line must be drawn like anything else in life. But the idea isn't to "cleverly" perv it up a notch by lowering the line.