Assalamu alaikum ustadh, I began practicing 5 years ago, Alhamdulillah. Before that, even after reaching puberty, I missed almost all Ramadhan fasts and prayers. Do I need to make up all those fasts and prayers? What is the expiation for them? JazakAllahu khairan.

Imām Ibn Bāz said: Whoever abandons prayer and fasting, then repents to Allah with sincere repentance, is not required to make up what he left. This is because abandoning prayer is major disbelief (kufr akbar) that expels a person from the religion, even if the one who abandoned it did not deny its obligation—according to the soundest opinion of the scholars. Allah the Exalted said: “Say to those who have disbelieved, if they cease, what has previously occurred will be forgiven for them…” [al-Anfāl: 38]. And the Prophet ﷺ said: “Islam wipes out what came before it” and repentance erases what came before it. There are many evidences for this, including His saying, the Exalted: “Indeed, I am the Perpetual Forgiver of whoever repents and believes and does righteousness and then continues in guidance.” [Ṭāhā: 82] And His saying, the Exalted: “O you who have believed, repent to Allah with sincere repentance. Perhaps your Lord will remove from you your misdeeds and admit you into gardens beneath which rivers flow.” [al-Taḥrīm: 8] And the Prophet ﷺ also said: “The one who repents from sin is like the one who has no sin.” What is legislated for the repentant is to increase, after repentance, in righteous deeds and to frequently ask Allah, the Exalted, for firmness upon the truth and a good ending. And Allah is the One who grants success.