When we practice Christianity without being born again we won’t have the power to overcome our sins. The Bible speaks of, “holding a form of godliness, but having denied the power therefore.” (2 Tim 3:5 ASV).
The power that we deny is what we should receive when we come to know Christ. That power should change us over time. If it doesn’t I would be suspect of my own salvation.
Don’t trust a form of godliness. Religion won’t save you. You must repent and turn from your old life and to Christ if you want to experience eternal life.