I don't know how old you are but I am almost 53, and I can   unequivocally state I did not know any twelve year old friends that were sexually active. I don't recall 12 yo girls performing oral sex on boys on the school bus, nor recall children engaging in sex acts in the school bathroom.  If a 12 yo girl was involved in this sort of conduct I would suspect she was a victim of sexual abuse by an adult. I have been a police officer for over 30 years and investigated  sex crimes as an investigator. I have seen the change in sexual immorality over the past 30 years.  Child pornography has increased exponentially since the invention of the internet.  If you know many 12 yo children that are engaging in sexual activity, you should then be reporting this activity to the proper authorities.  In NY State it is a crime for CHILDREN to engage in this behavior.