Here is the honest-to-God truth to if penis size actually matters, the size of the penis is only as important as the man who uses it.
This is why some women say that size matters, men simply don't perform as good. Men with a smaller penis size automatically put up a barrier and limit themselves mentally before they even drop their pants.
If you are self conscious about your size it will really come across then you are trying to perform. This is why it matters to women because if matters so much to you leading to a poor performance in the bedroom of course it will matter to her.
"Think Size Doesn't Matter!"
It is that easy and if you think it doesn't matter then she won't either. Focus on pleasuring her in other ways that work for the both of you. The good news is that many women consider a man with a smaller penis to be a more passionate, better lover overall!
This is because they focus on a bunch of other ways to have women scream their name in the bedroom. So stop worrying and start practicing on being the best lover she has ever has no matter what the size of your penis may be!