Girls only care about penis size when they're only looking for a physical relationship. When it comes to a romantic relationship, penis size doesn't matter.
what bullshit.... you sound naive and inexperienced... women, whom are looking for just a fling or physical encounter care more about bedroom skills and the person's sex appeal (which is largely character driven)... a dude that can drive em wild, tease them, get them hot and fired up, will be the one who gives them the mind blowing orgasm....
too bad that is all they dont care about... that would sort of makes it easy >:)
seriously,... with your very extreme limited experience and obvious dating life full of rejection after rejection, you shouldnt speak in generalities.