unless your costume is extremely elaborate, slutty, or has an incredible prop, nobody will notice you: congoers take pictures of impressive, hot, and/or characters they know when it comes to cosplay. You will be mistaken for characters from anime repeatedly as well, no matter how completely unrelated your costume is. (This happens anyway, yeah?) Having just done a cosplay of a friend's original character, I can testify to this first-hand. I amused myself by acting in-character around the friends who knew the character.
If you're not expecting to have pictures taken of you and/or you have a friend or friends who will enjoy your original character at the con, you'll have a good time. If you're an attention whore like me, just prepare yourself for complete anonymity.
