Based on many authentic hadiths Aisha was six years old when the Prophet Muhammad (PBUH) did the marriage with her. Aisha was nine years old when she started living with the Prophet (PBUH).

The age of Aisha at the time of her marriage to the Prophet Muhammad (peace and blessings be upon him) is mentioned in several authentic hadiths. Here are the specific references:

• Sahih al-Bukhari

Hadith 3894: Narrated by Aisha: The Prophet married me when I was six years old, and my mother handed me over to Him when I was Nine years old.

Hadith 5133: Narrated by Aisha: The Prophet married me when I was six years old and consummated the marriage with me when I was nine years old.

• Sahih Muslim:

Hadith 1422: Aisha reported that the Prophet married her when she was six years old and consummated the marriage with her when she was nine years old.

• Sunan Abu Dawud:

Hadith 4937: Narrated Aisha: The Prophet married me when I was six years old, and consummated the marriage with me when I was nine years old.

These all references are considered authentic and are widely accepted by Islamic scholars. These all are reliable sources that correctly count the age of Aisha at the time of her marriage to the Prophet Muhammad (PBUH).