Can't speak for the US, but here in Calgary, we learned about contraception in junior high, and most of us were aware that it existed by the time we were in div 2 of elementary school.
Why are their heads backwards?
I was wondering about that too.
I once knew a 7th grade girl who had two kids!
Was she in grade 7 due to being left back, or had she somehow managed to have two kids by the age of 12?