Why is it wrong for a person to start a family when they are, statistically, between a third and a fourth of their life. It is pretty common now, it is pretty common then. Terms like "little girl" are by definition arbitrary and misleading as well as confined to the culture in which the term is used. If vague generalities are the order of this thread, I'm pretty much done with this discussion.
I'd be done too, if I had to defend child rape. btw, and back to the subject of the thread, should I be jailed or even sued for stating my opinion that having sex with a child is wrong, prophet or not?
Well, I'm not sure why these ideas are hard for you, but I'll try to explain why having sex with children is wrong.
The core idea is that morality should be primarily about human suffering, respect and compassion, and having sex with a child causes them to suffer, both physically and emotionally. Children should be protected from adult sexual desire until they are old enough, physically, intellectually and emotionally, to choose their own sexual partners.
And your age in proportion to your lifespan does not change that. If you end up dying at ten, it was still wrong for a man to have sex with you when you are 9.
So you don't consider a 9-year old to be a little girl? Do you have any children?
I gather you actually have no evidence that 9-year olds in the 7th century were physically, emotionally and intellectually adult?