7.2" is big. You see plenty of bigger on this site, but the reason for that - quelle surprise - is in the name. A site that appeals particularly to massive guys from all over the world showing off and people who like to look at their goods isn't likely to hold a representative proportion of the male population.
I don't know the precise numbers but it wouldn't surprise me if you were in the top 2%, lengthwise. Stop worrying and enjoy.