I think your post exemplifies a real problem with a literal interpretation of scripture. When confronted with the fact that we know from science that Noah's Flood didn't happen as described in the Bible, your answer is basically: "Well, it could have happened, we wouldn't really know if it did or not, you haven't proven that it didn't."
The problem is that this need to maintain a literal interpretation causes people to deny reality and factual information, to doubt things that any normal person would have no trouble accepting. Basically, it holds you back. if you didn't have to cling to that interpretation, you could accept the truth of the matter and move on.
If you want to argue about proving the Flood wrong you can go here: