That's true. She was 6 as she became his sex slave but I really don't know what kept him from fucking her right away. Probably erectile dysfunction from smoking all the opium.
It's really not known how old she was, Abu Bakr didn't have many records on him and his family until he got on the prophets tip. Some say they were married when she was 15. From what I understand the description of her age at the time was a term that can mean between 8 and 16 but people accept she was on the younger side of it.
His first wife was middle aged when he was young though, cut him some slack. He married women for altruistic reasons, even his critics will admit that, the Qur'an is full of reasons for having multiple wives because women are too weak to survive on their own etc.
