Sometimes you will read that there is debate over Aïsha’s age and that she may have been much older than nine when she married Muhammad. Some of these claims are very strongly worded.
Recent researches have established beyond doubt that the age of ‘A’ishah (rta) at the time of the consummation her marriage with the Prophet (sws) was around nineteen or twenty. The Ahadith which report her age to be eight or nine years at the time of marriage are absolutely baseless.
People can “debate” what they like; but this is not an issue among scholars. Aïsha’s age on her wedding day is one of the best-attested facts of Muhammad’s life. All the early traditions state that she was nine, except for Ibn Hisham, who says she was “nine or ten.” This suggests that Ibn Hisham was not sure and so wrote an approximation. Aïsha herself was completely sure. To be precise, she was nine years and three months, plus or minus five weeks.