2 Corinthians 5: 21; It is an oxymoron to say you are a Christian and a sinner. You can be either but you cannot be both.
Colossians 1: 21- 22 lets us know we are holy and blameless. Is a crawling child a reptile and less human? At that stage, he is still learning. And it is the job of the matured adults around to encourage the child to try taking his first step and his next.
Just because you gave your life to Christ does not mean you automatically stop all bad habits. Through the help of the Holy Spirit, you can consciously start doing the right thing. Calling yourself a sinner is not humility, it is calling God a liar; Romans 8: 1- 2.