It was narrated that:
Abdullah said: “The Prophet married Aishah when she was seven years old, and consummated the marriage with her when she was nine, and he passed away when she was eighteen.”
حَدَّثَنَا أَحْمَدُ بْنُ سِنَانٍ، حَدَّثَنَا أَبُو أَحْمَدَ، حَدَّثَنَا إِسْرَائِيلُ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي عُبَيْدَةَ، عَنْ عَبْدِ اللَّهِ، قَالَ تَزَوَّجَ النَّبِيُّ ـ صلى الله عليه وسلم ـ عَائِشَةَ وَهِيَ بِنْتُ سَبْعٍ وَبَنَى بِهَا وَهِيَ بِنْتُ تِسْعٍ وَتُوُفِّيَ عَنْهَا وَهِيَ بِنْتُ ثَمَانِي عَشْرَةَ سَنَةً ‏.‏
GradeSahih (Darussalam)
English reference : Vol. 3, Book 9, Hadith 1877
Arabic reference : Book 9, Hadith 1951