5.5 is only average because asians take up the majority of the population in the world.
Average Asian is about 5, Koreans have it worst at average of 4.5-4.7"
White males are ~ 5.5-6"
Blacks are 6-6.5"
Thickness is a major bonus, no girl wants a pencil dick.
I myself am 5.5" long but I am more than average in terms of thickness. Trust me, I make my girl squirt and scream like a little bitch when I fuck her my hardest. Never had any complaints ;)