The younger the women the healthier the offspring.
Not really. The biologically optimal age is around 20 to 25.
At 11-12 years old the woman can bear children.
While some girls that age can, it is an utterly disgusting idea. An 11-year old girl is not woman. In some cases a girl that young could be able to become pregnant but not usually without considerable risks to the health of herself and the baby. She is a child herself and ill equipped to raise one properly. Even the babies of older teenagers (15-19) are at an elevated risk of low birth weight and perinatal death and an 11-year-old is not even a teenager, yet.
I know there are cultures that sanction the consummation of marriage at such a young age. That is savagery plain and simple.
Your arguments are sociological and psychological. Nature doesn't care about that. It had the wisdom of millions of years of evolution to be bothered by a glitch in the last couple of thousand years of human culture.
No, my arguments were medical and biological. The biological informs but does not dictate the sociological and the psychological.
Human males who are not fucked up are biologically programmed to sexually prefer women who are post-pubescent but early into their reproductive years. Normally developed heterosexual men want to most badly fuck those females who are fully developed sexually but have youthful characteristics such as clear, soft and wrinkle-free skin, firm shape and pert breasts etc. Most females become fully developed by the age of 16 or so and retain those characteristics until their mid twenties. This and pedophilia are completely different things.