(Even if she was 16, that's still underage)
No it's not
As a parent I can this with certainty... YES IT FUCKING IS!
by 13 a child has already experienced at least 5 years of atheistic "sex education" lessons in schools.
First, When I was in school we got half a semester of abstinence only sex ed in our senior year. By the time my kids were in high school they had the good sense to move it to half a semester in the freshman year and discard the idiotic "abstinence only" proviso, but still a far cry from your "five years of lessons" fantasy.
Second, Just exactly what is atheistic about sex ed?
This amounts to little more than paedophile grooming sessions.
How? Moreover I find it quite telling that I can point to more examples of religious authority figures grooming kids for sex in my hometown than I can for sex ed teachers nationwide.
In broader terms, this is the inevitable result of divorcing your society and legal system from Godly justice and morality.
First off, there is nothing moral about your so called god's so called justice.
Further more, if we hadn't divorced our legal system from your backward religion then your lot would still be burning innocents at the stake and torturing people to death in trials by ordeal. Oh, what a wonderful world that would be (/sarcasm)