Let say there is period of time where a born Muslim live in west and have no idea of anything about God, Islam, Prayer, Islamic laws and the person lives only according his desires and have ignorance about the matters of Islam. If the person realize God, and realize Islam and start to practice Islam, will the past sins be all forgiven?
Second, what happens to the Salaat and Fasting of that time, does it need to do Qada?
“... there will be there all that the souls could desire, all that the eyes could delight in …” (Quran 43:71)
“Eat and drink at ease for that which you have sent forth (good deeds) in days past!” (Quran 69:24)
“… They will be adorned therein with bracelets of gold, and they will wear green garments of fine silk and heavy brocade. They will recline therein on raised thrones. How good [is] the recompense! How beautiful a couch [is there] to recline on!” (Quran 18:31)
not hear therein ill speech or commission of sin. But only the saying of: Peace! Peace!” (Quran 56:25-26)
There will be no enmity between people nor ill-feelings:
“And We shall remove from their breasts any (mutual) hatred or sense of injury (which they had, if at all, in the life of this world)…” (Quran 7:43)
“And whoever obeys God and the Messenger – those will be with the ones upon whom God has bestowed favor – of the prophets, the steadfast affirmers of truth, the martyrs and the righteous. And excellent are those as companions!” (Quran 4:69)
“Crystal-white, delicious to those who drink (thereof), free from intoxication, nor will they suffer intoxication therefrom” (Quran 37:46-47)
“...rivers of water incorruptible; rivers of milk of which the taste never changes...” (Quran 47:15)
they shall have therein purified mates…” (Quran 2:25)
“And when you look there (in Paradise) you will see a delight (that cannot be imagined), and a great dominion.” (Quran 76:20)