Perhaps I may go into that later but I wish to understand others first. Is this acceptable?
When you have no Reason to believe in a deity, it's hard to explain Why you don't believe in a deity, other than by saying 'because I don't believe in a deity'.
Which would be essentially answering 'why am I an atheist?' With 'because I am an atheist.'
It is not untill someone can make a convincing argument for a god hypothesis, that a counterargument should come into play.
So if you want to hear Why I am an atheist. Let's hear Some arguments as Why not to be. If any of them make sense, you might sway me. If they don't, i'll yell you Why I don't 'believe' them. That's Why I must ask; 'why aren't you?' Before I can give you THE answer you seek.
That being said. If you don't want to explain Why you believe, that's fine. People do that here more than enough already. :p