If you are a Christian then you are an overcomer against sin and the Devil. Those who have permanently fallen away were not saved to start with (1 John 2:19). Those who are truly saved are destined to endure to the end but it does not mean there are moments of quitting and chickening out. But remember it is not a permanent and complete falling away from the faith. Christians can be so discouraged that they should expect punishment to get them back on track.
It is very easy to chicken out but it is the grace of God that makes the Christian endure to the end. It is the wonderful assurance in John 10 that the sheep of Christ hear His voice, they know Him, He knows them and they follow Him. I have no doubt that by the grace of God that Christians may not be perfect but God works them to perfection as Philippians 1:6-7 declares that what God has started - He is going to finish it!