I realized today that my faith in science prevents me from being an atheist, as we cannot scientifically prove or disprove the existence of an extraterrestrial intelligence capable of creating life, which apparently makes me an agnostic.
Do I get to join a special club now?
We can't scientifically prove any of the major beliefs, but that doesn't stop you from believing in evolution or plate tectonics. Inference is a valid part of scientific understanding and study. It HAS to be, because you're talking about an epistemological problem, not a scientific one.
Take magic, which is actually a really good analogous example. The arguments against its existence are almost completely synonymous with arguments regarding god's existence. Ultimately, a lot of what you'd rely upon is an inference to the best explanation. If you are going to allow for this to give you positive beliefs (evolution, gravity), then you HAVE to allow for it in the negative (magic, God).
So, really, if you have faith in Science, then you shouldn't be considering yourself agnostic unless you believe there's something fundamental about God that renders humanity incapable from even gathering evidence. That's all agnostics technically are--they proscribe to a specific stance regarding the nature of belief/knowledge.
In its weakest (and most applicable) form, that is the stance that you cannot believe something unless it's reasonable to think that you could
know it was true. In it's strictest form, it's pure skepticism--that you cannot hold a belief about something unless you know it, and that you can't know anything a posteriori.
In its strictest form, even science is considered invalid. In its weakest, your reasons shouldn't be sufficient to render atheism or theism unreasonable to accept.
Really, most agnostics consider themselves such because they are speaking about doctrine, not theism vs. atheism. It's actually a different discussion. In that case, you've accepted theism, but you don't think it's possible for you to know the truth with regards to specifics about god/gods and its will.