Abu Bakr married twice, and fathered four children, before the beginning of the Revelation (i.e. at least 13 years before the Hijrah): 'Abdullah, Asma, 'Abdur-Rahman, and 'A'isha. This is uncontested and well-known to the Muslims. 'A'isha was betrothed to Jubayr ibn Mut'im ibn Adi, before Abu Bakr accepted Islam in the first year of the Call (12-13 years before the Hijrah). This is uncontested. When Abu Bakr planned to go to Abyssinia during the fifth year of the Call (8-9 years before the Hijrah), Mut'im broke off the engagement because Abu Bakr had accepted Islam. This is uncontested.
Throughout history, Ayesha’s age at the time of her marriage was not raised as a contentious point, by the critics of Islam. This implies they viewed the marriage as conforming to the norms of society; the age old tradition in most societies is girls marry early, usually just post-puberty. Apart from the cultural precedents of the time, such practices were also common among the Biblical Prophets. According to the Bible, Prophet Abraham (SAW) was 86-years-old when he married Hagar, who was young enough to give him a child, the age gap must have been considerable. King David was given a beautiful young virgin in his old-age to keep him ‘warm’ (1 Kings, chapter 1, verses 1–4, New International Version). There is general consensus among Christian scholars that Mary, the mother of Jesus was pregnant at the age of 12, and was married to Joseph between the ages of 7 and 9, Joseph was considerably older, by some accounts put him at 90! Prophet Muhammad (SAW) was around age of 54 when he married Ayesha, she was of a similar age to Mary as per report in the books of Hadiths.