Chances are... if you set your mind to something... you can probably achieve it. I not saying everyone is good at everything. (I mean, can somebody please tell those people at the beginning stages of American Idol that they can't sing?). But... it's also equally important to not talk yourself out of working hard at something that you could be really good at if only you'd stop listening to your inner critic.
God gives us all talents and gifts for a reason. Your interests and the things that you delight in are His way of helping you figure out what those talents and gifts are. Embrace that! You're the only one who thinks the way you do, and it'd be a shame to waste that because you didn't think you could (or should) try. So... get out there and try!