If I didn't know masturbation invalidates fasts, and didn't know what Ghusl Janabah was at a young age, must I repeat prayers and fasting? I don't know for sure this happened during Ramadan, as it was a couple years ago. What should I do?
If you did not know that masturbation invalidates the fast and you committed masturbation during the days of the month of Ramadan there is no Kaffara on you but Qadha of the fast of that day. If you did not know that Ghusl of Janabah is compulsory for a valid fasting you need to keep Qadha (Qaza) for every day of fasting which you are sure that you were in the state of janabat. Wassalam.