This is going to come over as a bit "lecturey" and repetitive of other posts, so 'soz'. 
There is a natural evolutionary conundrum. Societies that have well nourished children see earlier puberty than those societies closer to starvation. It's a built in evolutionary population control.
The issue is that well nourished societies can also afford to support ethical and moral systems which determine norms beyond and without nature.
This will persist and only education, coercion and protection will reduce (but never prevent) sexual activity at an age deemed by us to be
'too early'.
At the same time consumer society is sexualizing everything from clothes to cars, chocolate to coca-cola. There is no room for "innocence".
The reason why consumerism has latched onto sex is because it is taboo and too exciting. Young people get exposure to unnatural sexualized content whilst "normal sex" is swept under the carpet.
If we want young humans to develop emotionally before sex we have a lot of parenting to do to battle against nature, consumerism and taboos.