The beginning of Muhammad's prophethood is known as "The Call",
it consist of two periods:
The Meccan period was 13 years and The Medinah period was 10 years.
The Qur'an also known is revealed in both periods, therefore there are: Qur'an of meccan period and medina period.
The migration from Mecca to Medina is known as "Hijrah". A.H means after Hijrah.
Muhammad was married before The Call and she died at the 7th year of Mecca period.
The well-known historian Ibn Jareer al-Tabari writes at page 50 of volume 4 of his 'Book of History':
"Abu Bakr married 2 ladies in The pre-Call era.
Fateelah was the first, from whom he had 2 children: Abdullah and Asma.
Umm-i-Rooman was the second, from whom he also had 2 children:
Abdur Rahman and Aishah.
All the 4 children of Abu Bakr were born in The pre-Call era from the above-named 2 ladies."
Abdur Rahman fought against the Muslims in the battle of Badr (year 2 A.H). His age at that time was 21-22 years,
Abu Bakr planned on migrating to Habshah 8 years before Hijrah, he went to Mut`am -- with whose son Ayesha was engaged to -- and asked him to take Ayesha in his house as his son's wife. Mut`am refused, because Abu Bakr had embraced Islam. And subsequently his son divorced Ayesha.
When Abu Bakr was approached on the behalf of the Prophet, he replied that the girl had already been betrothed to Jubair, and that he would have to settle the matter first with him.
According to narrative in Bukhari (kitabu'l-tafseer) Ayesha is reported to have said that at the time Surah Al-Qamar, the 54th chapter of the Quran, was revealed, "I was a young girl" she said.
The 54th surah of the Quran was revealed 9 years before Hijrah.
Aishah was a widow for 40 years since after his death until she passed away.
Asma died in 73 after Hijrah at the age of 100 years, she was 10 years older than her sister Aishah.
It is also reported in books of hadith and history that no one under the age of 15 years was allowed to take part in the battle of Uhud. All the boys below 15 years of age were sent back. Ayesha's (RA) participation in the battle of Badr and Uhud clearly indicate that she was not nine or ten years old at that time. After all, women used to accompany men to the battle fields to help them, not to be a burden on them.
When the Prophet died Aisha had written over than 2,000 hadith, a 2nd largest.