Well, if you speak this way about your own intelligence and don't even have a handle on whether you are smart or relatively smart or not then I guess in your case the test was in fact wrong.
Are there differences in people? Obviously. Are there differences in the level of material people can learn and use fluently? Obviously again. Are people that can fluently use some types of material generally more capable in a group of areas we usually think of as requiring more intelligence, yes again. So pretending there is nothing at all to intelligence differences generally is clearly not in keeping with known data.