"Good to go"? Sure, if you just breed girls to get the dowry. If, on the other hand, you have children because you love children, you probably won't let your 13-year-old daughter marry some 40-year-old man, would you, tteclod? Oh, you weren't thinking about girls as daughters, just as fuck-dolls, were you? Well, here's news for you; every girl is someone's daughter.
When my parents were expecting me, back in 1969 when they were 21 years old, older relatives muttered "children shouldn't have children". Was that also part of the modern society?
Why the scare-quotes around "bleeding"? You do know that it's literal bleeding, for about a week every month, for some 40 years of our lives, right? The bleeding often starts when the girl has reached a certain weight, not when her body is physically and mentally ready to have children.
"Some of the sub-Saharan's" are married off at 13, and many of them are mothers by the age of 14. Quite a few die in childbirth, though.
Ten years late, for what? Are you in a hurry? You do know that in the societies where it's OK to marry off your 13-year-olds, it IS marriage that is the key, right? That good to go 13-yo will grow up and soon be early 20's, and you'll still be stuck with her. What then?