"there is no way for you to test a theory that God does not exist, so you cannot say that you have evidence"
Well in a sense there is: if you define God as omniopotent, omniscient, omnibenevolent, etc. Then you can make predictions about the universe that such being would make, you would expect a perfect God to make a perfect world, for life to be perfectly designed, and yet we see that is not the case, that can be interpreted as evidence against a biblical God.
It is not by any means the only argument against God, that's the thing, there are just so many different lines of reasoning (like my lovely kangaroo) that all converge on the same answer that it's simply not logical to believe in one.
But I'm beginning to learn to pick and choose my battles; you are a creationist, first things first, i understand you don't have much time to go through these arguments, fair enough, they are not simple if you have no scientific background.
But i really do urge you to find a popular-science book on evolution (by an evolutionary biologist like Dawkins), if you manage to read 30 miniutes of it a day, in a month your understanding of the living world around you will be transformed! The universe trully is a remarkable place, understanding it is more rewarding than you can imagine.