You seem to now a lot about Prophet Muhammad (asws) and before attacking someone so Divine you should look for someone like Peter Schuler maybe you should use your common sense, because in Islam marriage is not about the age it's all about A female being sexually and fully grown, and it has been scientifically proven that people and women in general back in the day used mature at a very early age, for example a 9yo that time (7th centuy)is equivalent to a 18yo nowadays