If Saul (who became Paul) could change, and even be a leader of the Christian movement unto martydom, so you too, regardless of your sin & rebellion, can convert. Read how hard the heart of Paul once was against God.....
Then Saul,
still breathing threats and murder
against the disciples of the Lord,
went to the high priest.
And desired of him letters to Damascus to the synagogues,
that if he found any
of this way, whether they were men or women,
he might bring them bound unto
Jerusalem.
Acts 9:1,2