What is how old was gohan when he fought cell?

Gohan was 11 years old when he fought Cell for the first time during the Cell Games. However, he was 9 years old when he first fought Cell in his imperfect form during the Androids saga. After training with his father and with the help of the Saiyan power-up, Gohan was able to transform into a Super Saiyan 2 and defeat Cell in his perfect form.