Think about it, my daughter being five years old compares her hair to other girls all the time. This obviously is something she has become self contious of due to most of her friends having long flowing locks. She was slow growing hair and it is thin and not as long as most of her friends (sadly she gets this trait from her mother). She always says, "so and so has such pretty long hair like Rapunzel, I want hair like her" no matter how often I tell her that her hair is beautiful she still compares her hair to other girls.
As girls grow they are always comparing themselves from academics to extra curricular activities comparing others being better gymnast, dancers, cheerleaders,etc. I am all about some healthy competition, I feel it is a good thing however have we as a society become so competitive that we have taught our girls that even if they are not ranked the best the aren't the best. If we are teaching our girls to be the best THEY can be then they ARE THE BEST.