Democrat or Republican?

I am not sure if I am a Democrat or a Republican. I know that is pretty dumb that I don't know, but I don't, sue me. I know what my mother and step dad are and one is a Democrat and one is a Republican, but what am I? I took a quiz on the internet and that says I am a Democrat, but I am not sure what that means....any works of wisdom would be nice. Thanks :)