Hey dude... here's the thing, only petty chicks would talk about that. Real women are concerned with more important matters, like how long can this guy go, what does he do for me, and is he good when he does it?
Think about it... if you were 10" long and weighed 350 pounds, & fat as Jared before Subway, would a chick care about your size? No way... If you were 5" and an MMA fighter that could go all night, is she gonna care about your size... she'd likely love it, and size wouldn't be a factor.
Don't compare yourself to pornos, if that's what you're doing. That's like saying, I can't play guitar as well as Eddie Van Halen so I should just quit playing altogether.
Make sure that whatever woman you are with gets off. Put her pleasure before yours and your size will not matter to her.