Five and a half inches is the average length of the American penis, so chances are very good that you have all the equipment you need. Relax, watch some porn, learn how to use what you have.
Joe: "Cocky bastard knows how it's done, I guess. Wish he'd teach us something... No homo!"
Sam: "Haha, 'no homo' indeed! I still say you need a big penis."
Joe: "Aaaaand that's why you're still a virgin."