Reference: http://mufti.af.org.sa/ar/content/عليك-القضاء-مع-إطعام-مسكين-عن-كل-يوم
Question: I inform your excellency that I started my menses when I was young – approximately 13 years of age. And [thereafter] for 4 years the month of Ramadhaan passed by and I did not fast, because of my ignorance [of its obligation upon me] and not [really] knowing [about it] since we used to live in the desert. At that time I did not [even] pray the obligatory prayers. Bearing in mind that I am now 38 years of age, and am suffering from an inflammation of my bowels, what do you advise me with? Am I required to fast in this condition, or should I [suffice with] making an expiation, bearing in mind that I had made the intention to go for hajj this year [as well]? Advise us, and may [Allaah] reward you.
Response: You are required to make-up the fasts [of Ramadhaan] you missed for those 4 years, in addition to feeding a poor and needy person for every day [of fasting] you missed [during that time]. That is because you delayed making-up the fasts without [a legislated] reason. [In addition,] you must [also] repent to Allaah. [All of this] does not prevent you from going for hajj. As for the [obligatory] prayers you missed during the period you mentioned, then you must sincerely repent [to Allaah] for that, and you are not required to make-up [these prayers you have missed] because of the difficulty in [doing] that.