You are not agnostic
Some people claim to be agnostic instead of atheist because they believe it is a less severe view of the disbelief of a God. They are mistaken in their understanding of the term Agnostic. It is not a step down to a softer form of atheism. Agnosticism and atheism are two completely separate categories of belief.
The definition of agnostic is:"a person who believes that the existence of the ultimate cause, or God, is unknowable." This does not mean the person believes there is a god. Nor does it mean the person believes there is not a god. It is only referring the knowledge about a god.
The definition of atheist is:" a person who disbelieves the existence of a supreme being. " This is referring directly to the belief that a god exist or not. It is not referring to the knowledge about a god or whether that knowledge is knowable.
A person can be an agnostic atheist or an agnostic theist. That's right, you can believe in a god while simultaneously believing that the knowledge of the god you believe is unknowable. You can believe there is no god while simultaneously believing that there might be a god, but the knowledge is unknowable.
How do you determine if you are atheist? That's easy, just determine whether you believe in a god or not. It is okay to say "I don't know", but that is not the question. We don't know if unicorns, leprechauns, or big foot really exist either. But you could still believe they do exist without knowing for sure. The question is, do you believe, regardless of your knowledge. If you say you don't know, then you probably fall in to the category of atheist. Think about all of the other claims people make about magical creatures. You can say I don't know if all those things exist, but it is pretty obvious that you don't believe in them. You don't need knowledge about each crazy claim to know you don't believe in something.
How do you determine if you are agnostic? This is referring directly to the knowledge of a god. Do you believe the knowledge of god is unknowable? That seems to be a severe claim. Man has had many new advances in knowledge in last centuries that we could have never imagined. In light of this it seems a far stretch to think any knowledge is eternally unknowable. How can we claim that any knowledge we don't posses today will never be discovered? Do you really believe this?
So ask yourself these questions and determine which category you fall into. You may be surprised. Whether you are agnostic or not, you can be theist or atheist. Where do you see yourself now?