Size does not matter when it comes to performance in any area of life, and that includes sex also. Most vaginas are only about 4 inches in length. Also a womans vagina is really sensitive at the clitoris and at the first two inches of the opening of the vulva. It is here where most nerve ending are located and if a penis can reach this area, then it is enough. Also most women are not obsessed about size as much as men are.