The biggest problem with a guy who is very, very short is that he will invariably try to get in as far as he can with his 3 inches to try to "feel" longer to the woman. Now, the shaft tapers out wider at the base, so when the tapered part is being shoved into the soft delicate skin around the opening of the vagina, it stretches, pinches and does not feel good at all. Any slight benefit of being deeper is so outweighed by the discomfort of the stretching of the opening that it is the worst approach a very short guy can take. But it is almost impossible to discuss or bring up without hurting his ego, so you just have to grin and bear it.
Fortunately, guys that short are very rare.
For this reason, when I see a guy with a very, very short member, I find myself thinking, "Oh no" much more than a guy who is very, very long or very, very big (also very rare).
What I care most about a guy is his personality and how he make me feel. If I love the guy, I will love his cock no matter what it looks like or how big it is. Guys care about size.
Be big on the inside and it won't matter how big you are on the outside.