I disagree (and for the record, not because I want to have sex with someone that age.) A 13 year old can be just as mature and smart as someone 18+, the reason

I disagree (and for the record, not because I want to have sex with someone that age.) A 13 year old can be just as mature and smart as someone 18+, the reason the law exists is because it isn't the case nearly all of the time, and there's no simple way of judging on a case by case situation, so it's better to protect the 99(.9?)% of 13 year olds who need protecting. This doesn't justify any adult having sex with a 13 year old, regardless.