I don't really believe in a god exactly, however I'm not ruling out that there is a higher power. I just know for this period in my life, I have no reason to believe that there is a god. When I was younger I was brought up as a Christian, had my holy communion, but never got confirmed.
While I do not go to mass (apart from weddings and funerals) I still live a good life. I'm always helping people out and always try to help those less fortunate. I don't do so cause i'm a 'good christian'...I do so cause I'm not a dick and was brought up well by my parents.
So I guess not believing in anything but not ruling out any possibilities makes me agnostic right?