They are wiped away. The Prophet ﷺ told ʿAmr ibn al-ʿĀṣ: "Do you not know that Islam demolishes what came before it?" and Allah says of the disbelievers: "Tell those who disbelieve that if they cease, what has already passed will be forgiven them" (Quran 8:38). This includes shirk itself and everything that came with it — you begin with a completely clean record, with no missed prayers or fasts to make up from before your shahādah. The one thing entering Islam does not automatically settle is the rights of other people: debts you still owe, or property of others still in your hands, should be returned where you are able, since wrongs done to people are meant to be settled in this life rather than left to the Day of Judgement.
Evidence — the daleel
On deen2u
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.