"Very few had made a specific choice out of the pressure of a heated moment with the help of their parents." 
Because we all want to involve our parents in our sex life???
"When I used to teach there were generally only 2 reasons why young girls had sex; either they were drunk or they felt pressure to show a boy they loved him (or both)."
May I suggest a reason you appear to unaware of. Because sex is enjoyable and girls
have libidos too.
"armed with contraception"
Er, without sex ed, and obviously drunk or pressured by a boy, how are they supposed to find out about contraception or how to access it? Or make a decision about which contraceptives to use. Or learn about diseases like chlamydia that don't have obvious symptoms but can cause infertility?