Here's Paul after his conversion. He was a mature Christian, yet read what he stated:
1 Tim 1:12 And I thank Christ Jesus our Lord who has enabled me, because He counted me faithful, putting me into the ministry, 13 although I was formerly a blasphemer, a persecutor, and an insolent man; but I obtained mercy because I did it ignorantly in unbelief. 14 And the grace of our Lord was exceedingly abundant, with faith and love which are in Christ Jesus. 15 This is a faithful saying and worthy of all acceptance, that Christ Jesus came into the world to save sinners, of whom I am chief.
"Of whom I am chief" is in the present, continuous tense.
The Apostle Paul, called out by God the Father and Christ, didn't consider himself righteous or holy. He saw himself the chief of sinners in comparison to the righteousness of Christ.