You aren't a position main if..

You have under 50% win rates on all champs in that role, and have insanely low KDA's. Because chances are, you aren't winning games unless you're carried and you aren't skilled enough to win lanes. So please, if you enjoy champions in that position, play normals to get better before you haul off to ranked. I think the ranked community would get much better if there was more self-awareness about your own ability to play specific positions. Normals are there to learn champions, test builds and just gain experience without the threat or pressure of people who actually want to climb flaming you for feeding or anything.