It is true most girls don't know how to estimate length, they are horribly poor at that! However, girls regardless of anything will know your girth by the way they feel you down there. I think what matters most is girth over length to most women, length matters only when it is too short or too long as for anything between 5.5 to 7 inches, to most girls it may appear same length as long as there is equal girth. That is how I feel it!