It took my several years. I tried living on my own power and wisdom for most of my teenage years. It was a complete disaster. I was miserable. I made dumb mistakes and I had no power to overcome even the smallest sins.
Are you a believer? Do you have God’s Spirit living in you? If not, it is time to turn from a life without Him and cry out for His salvation and the incoming of His Spirit. Only this can bring the change your heart desires.