You are not a sinner merely because you do sinful things. Though that's true. You are sinner in the first place because from the moment you were conceived in your mother's womb, you were bent in the wrong direction (Psalm 51:5). That is, your heart longed for the same independence from God that Adam and Eve pursued when they ate of that stupid fruit in the garden. You've inherited their rebellious heart and attitude, and not only that, if you were honest, you would admit that you have actively invested a lot of your time and energy into cultivating that rebellion.