You know, for a guy puberty is embarassing and all, but your body doesn't really change much. You get physically larger and your genitals develop into their mature form. But everything you have is already there. Sure, you have to deal with spontaneous erections which can occur at the most inopportune moments, but that's nothing compared to....

puberty for girls. You don't just get larger, all of a sudden your chest starts growing out requiring special clothing to keep it in check. And then once a month, for no apparent reason, you bleed out of your crotch. That has to be quite traumatic the first time it happens. And I'm sure the staring from boys (and some men) can be a little unsettling. I can understand why a girl might be really reluctant to dress in anything other than baggy clothing and be uncomfortable in public. I could definitely see it as being a relief to be able to deny those things about yourself and regress to being pre-pubescent again.