You are again misquoting,She married her at the age of 9 and not 6. before Talking about mental maturity of Ayesha-know this -many of complicated islamic jurisprudence is based on Ayesha-s interpretation of Quran and Prophet Muhammed sayings.If Ayesha reasons it in a certain perspective,that is considered the most worthy interpretation above all.and also note - it is this Islamic law that is studied in the highest of law schools and forms significant part of many countries civil and crimnal law system