Question: Is it obligatory on me to make up for the missed days of fasting in Ramadaan, especially as I did not know that it is obligatory to make up for them? This occurred at a time when I was helping my family with many chores outside the house. For this reason, my father used to tell me not to fast because I was young. Now I doubt that there are some days of fasting which I missed. Must I make up for them consecutively? Must I give food to the poor in compensation? How can I do this, and from what kind of food?
Answer: Whoever is alive during Ramadaan and is eligible to fast must fast except if he has a Shar`ee (Islaamically lawful) excuse, such as traveling or illness during which it is difficult to fast. If the case is as you mentioned that you were eligible to fast, then it is obligatory for you to make up for the days you did not fast and make Tawbah (repentance to Allaah) and Istighfaar (seeking forgiveness from Allaah)… read more here.