It was narrated from 'Aishah that the Messenger of Allah married her when she was six years old, and consummated the marriage with her when she was nine. (Using translation from Nasāʾī 3255)
أَنَّ رَسُولَ اللهِ ﷺ «تَزَوَّجَهَا وَهِيَ بِنْتُ سِتِّ سِنِينَ وَبَنَى بِهَا وَهِيَ بِنْتُ تِسْعٍ»