Even if she was 16, that's still underage
No it's not. Besides, by 13 a child has already experienced at least 5 years of atheistic "sex education" lessons in schools. This amounts to little more than paedophile grooming sessions.
In broader terms, this is the inevitable result of divorcing your society and legal system from Godly justice and morality.
1. You're right, 16 legally the age of consent in the UK. However, a 41-year-old fucking a 16-year-old is still gross. Even grosser is the "stash of images and videos depicting child abuse and bestiality" the police found in the guy's house.
2. So you're saying sex ed starts in second grade? lol wut
3. From my experience, "sex education" in schools amounts to having some fuckwit youth pastor come into the classroom, tape kids' arms together, and desperately try to make some kind of point about "saving yourself for your husband/wife". Completely useless, but not pedophile grooming sessions.
3.5. Is no one concerned about WHY a thirteen-year-old is "sexually experienced"? Was she molested? WTF is going on?
4. Actually, the inevitable result of divorcing your society and legal system from "G-dly justice and morality" is that
believers follow their religion's rules without making those rules secular law. You know, because the bible is a terrible source of morality and things like "empathy", "fairness", and "common sense" work much better.
In summary, you are insulting, wrong, and insultingly wrong. Please die in a fire, preferably a fire from the colony drop Ironbite is preparing.