How to know if I am a Christian

The only way I know I am a Christian is that I have faith in Christ. The only way I know I have faith in Christ is that I bear good fruit.  Which means, if I look and do not see good fruit in my life I need to take heed that my faith is lacking.  If this scares me, good!  It is a healthy reminder to seek the Lord and ask Him for more faith-building grace.  If this does not scare me, then I have reason to be really scared.