If you believe in Jesus as God the Son; together with the Father, and Holy Ghost; then you are a Christian. Because, as a true Christian you believe in only the one God/Trinity; and NO OTHER!
Now, you may "profess" to be a Christian, and also "profess" to be a witch. In fact, you will be neither the one nor the other. A true Christian does not believe in any God except Jesus as the son of God, and that God the God of the ten commandments, "Thou shalt have no other Gods before me." A true witch will accept Jesus as a wise, and learned man. But not, as a God.