Is it possible to repent from zina (unlawful sexual intercourse) for the first time, and is it obligatory to carry out the hadd punishment for zina upon oneself?

It is out of Allah Almighty's mercy towards His servants that He accepts the repentance of whoever repents and turns away from their sin. Allah Almighty says: "Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful."" [Az-Zumar: 53]. And Allah Almighty says: "Except for those who repent, believe and do righteous work. For them Allah will change their evil deeds into good ones. And ever is Allah Forgiving and Merciful." [Al-Furqan: 70]. In the Hadith (definition) Qudsi: "O son of Adam, as long as you invoke Me and hope in Me, I will forgive you for what you have done, and I do not mind." The conditions for sincere repentance are: immediately ceasing the sin, regretting what has passed, and resolving not to return to it. One must increase good deeds, such as maintaining prayers in congregation, frequently remembering Allah, hastening to marry, accompanying people of virtue and righteousness, and avoiding everything that incites lust. What the questioner did by concealing himself and not informing anyone of his sin is correct, as Islamic law has prohibited open transgression.