Not only was it a custom in the Arab society to Engage/Marry a young girl it was also common in the Jewish society.
The case of Mary the mother of Jesus (peace be upon him) comes to mind, in non biblical sources she was between 11-14 yearsold when she conceived Jesus.
Mary had already been "BETROTHED" to Joseph before conceiving Jesus. Joseph was a much older man. Therefore Mary was younger11-14 yearsof age when she was "BETHROED" to Joseph.
We Muslims would never call Joseph a Child Molester, nor would we refer to the "Holy Ghost" of the Bible, that "Impregnated" Mary as a "Rapist" or "Adulterer".
According to the Priest of Saint Mary's Catholic Church: "Mary was approximately14 yearsold when she got pregnant with Jesus. Joseph, Mary's Husband is believed to be around 36 years.
Mary was only13 yearswhen she married Joseph. When she first was arranged with Joseph she was between7 to 9 years old."
According to the"Oxford Dictionary Bible"commentary, Mary was12 yearsold when she became impregnated.
So if I want to be as silly and ridiculous as many of the Christians, I would respond to them by saying that Mary was psychologically and emotionally devastated for getting pregnant at a very young age. And speaking of "child molesting", since most Christians believe that Jesus is the Creator of this universe, then why did GOD allow himself to enter life through a12-yearold young girl's vagina?
Please note that we Muslims love and respect Allah Almighty, Mary, Jesus and Allah's Messengers and prophets that were sent to the People of the Book (The Jews and Christians).
In other words, we Muslims would never make fun of Christianity through such childish topic like this one as many ridiculous Christians do make fun of Islam through our Prophet's Muhammad (peace and blessings of Allah be upon him) marriage to Aisha (peace be upon her) .