WHO MUST FAST AND WHO IS EXCUSED FROM FASTING

The first condition for one to be obligated to fast is to be Muslim. In this world, the non-Muslim is not requested to fast, however, in the Hereafter, he will be punished for neglecting to fast, as he will be punished for his blasphemy. Rather, the obligation on the non-Muslim is to embrace Islam, then afterwards, to fast Ramadan.
Secondly, it is the pubescent Muslim who is obligated to fast. The child is not obligated to fast. Rather, it is an obligation on the parents or the guardian of the boy or girl to order him to fast once he is 7 (lunar) years old, with the condition that the child’s body can withstand that fasting, and he would not be harmed by it.