Yes we can overcome sin, or rather the temptation sin presents, but yet we will stumble, there are many factors involved here. One is our time in country, how long have we been walking with the Lord, the longer we walk with with Him the more we understand His love, mercy and grace towards us, ...filthy rotten undeserving sinners, please don't take this the wrong way, but you are young, you haven't sinned as much as I have in our walk with our Lord, when I look back over my life with Him it's amazes me that He still puts up with me, but that's Agape love!
When we are born again the Holy Spirit washes us, cleanses us from what we think are gross immoral physical sins, we are constantly on the lookout for them and vow we won't do them any more, but that is just the physical side, there is still our spiritual lives and the more we learn of our Lord, the more we allow Him to conform us into His image the more we see how much we sin spiritually in our minds, ...our thoughts, will, desires.
Sin is empowered by the power of satan, that's why Paul calls him the prince of the power of the air, he is the most powerful of all of God's creation and we puny humans are so arrogant that we think we are some kind of a match for him, ...that is why it takes the Holy Spirit to overcome sin in our lives, both physical and spiritual, we say water will always seek it's own level, the sin nature in our mortal bodies is like water, always, 24/7 trying to seek it's level,to rule us, it's inescapable until we no longer live in this mortal body.
That's why I infer I know more personally about sin than you do, because I have sinned more than you even though I have said in my heart since day one I wouldn't. All of our sin, past, present and future (those that we will commit, today, tomorrow, next week etc.) were taken care of, paid for on the Cross and the lesson I would like to share with you is it's all GRACE, GRACE, GRACE, ...that is what my sin has taught me, like Paul said, where sin abounds Grace abounds more, that has freed me, set me at liberty to REST, REST in the finished work of the Cross and enjoy my walk with my Lord, I don't want to sin, I'm coming to abhor sin, but the truth is I do, but like Paul said, it's no longer me, but sin that lives in me, ...and that allows me to rest, leaning on the bosom of my Jesus.