not agreeing with some of the statment of faith does not mean you are not a christian...christianity is determined by your faith/belief in Jesus Christ as Lord and Savior. Salvation is a free gift of grace by faith.
Why do you think you are not a Christian ? If you have accepted Jesus Christ as your Saviour and follow His teachings and read the Bible , tell, others about His saving grace , you have nothing to worry about .
We are all from differing backgrounds and denominations but our common goal is Jesus Christ and serving Him