I keep trying to be a Christian but why do I end up remaining an agnostic?

(I think this is a troll, but...) Your understanding of what a Christian is is incorrect. Stop trying. If you don't believe what you do understand then you are fooling yourself, you are in rebellion. Obey what you do understand and ask help on what you don't understand from true Christians, and the Bible and its expectations of us will be understood and lead you to a decision to receive personal Salvation, which is the true Christian life.