The had for illegal premarital sex for non married people is covered in the Qur'an:
The [unmarried] woman or [unmarried] man found guilty of sexual intercourse - lash each one of them with a hundred lashes, and do not be taken by pity for them in the religion of Allah , if you should believe in Allah and the Last Day. And let a group of the believers witness their punishment. (24:2)
This ruling applies on you if either you have been caught in the act, 4 witnesses can seen you do this, or you have confessed it to a person of authority (a Judge for example). If not you can still repent from it a sincere repentance and lead a good Muslim's live (marrying a chaste girl etc.). This is the best work around you have. And you can stay in fear of a punishment in the hereafter and hope that Allah may forgive you. This certainly depends on how you lead your further life.
For a death penalty you also need a court, witnesses, confession etc. but as said above it doesn't apply for you.
Ma'iz ibn Malik came to the Prophet (ﷺ) and admitted fornication twice. But he drove him away. He then came and admitted fornication twice. But he drove him away. He then came and admitted fornication twice. He (the Prophet) said: You have testified to yourself four times. Take him away and stone him to death. (Sunan abu Dawod)
Allah's Messenger (ﷺ) as saying: Receive (teaching) from me, receive (teaching) from me. Allah has ordained a way for those (women). When an unmarried male commits adultery with an unmarried female (they should receive) one hundred lashes and banishment for one year. And in case of married male committing adultery with a married female, they shall receive one hundred lashes and be stoned to death.