"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"

How could you say that being a Muslim.. Don't you know that under Islamic shariah law, a woman becomes an adult the day she gets her first period....

Our Prophet (pbuh) married Ayesha when she was 9 years old but he did not consummate the marriage till she got her periods at 12 and only then she went to stay with him and the marriage was consummated.