Antiquity shows life expectancy was low throughout most of the World. People did not have schooling and work to think about, especially women. Puberty was generally the sign showing one was at the age for marriage. No one took issue with people marrying young, and the word paedophile is a modern term used to label people who intentionally seek out underage children for sexual activity and grooming.
The Bible makes it clear, if you disobey God's Commandments, then you are at war with Him and His Messenger. The Qur'an is the Final Revelation from God, and is a clear warning for non believers. Leave the Holy Cities of Arabia, seek peace terms or fight.
Secular Western Revisionist Historians have looked at the archaeological data and concluded Islam was for the most part not spread through violence many people like to think.: