In terms of religious language marrying a 12 years old is also not acceptable because for example in Islam for an individual to express any sort of will in any matter he or she has to be an adult. I think this also probably holds for jewish and christainity faiths.

Somethings have not been changed from the past to present. Those are the rules of modesty, moral values and etc etc. These acts will and were the same that people used to commit in the past. So there cannot be any need of revising any religious laws because those acts remain the same in nature even today.