If you get right down to it, it's impossible to know the truth about what happened five minutes ago. Perhaps our memories are false and the evidence is planted. Same with the Bible, or for that matter any book which claims to be non-fiction.
Theists often claim God as their star witness. The problem is that in order to claim He was there and so claim historical authority on the origin of life, or the universe, you must first establish God's existence by other means entirely or your reasoning is circular.
Science looks for the best natural explanations. It has to make certain assumptions, things like the reliability of our collective memories and the constancy of physical laws (most of the time), but these are all assumptions which have yet to be contradicted. If you want to question science as a whole, you need to find a way to put these basic things in real doubt, and that's hard.
The atheist material is great to have with you, because there's so little of it around and it'll always be a surprise to an evangelist. Where do you get yours?