Spring = 'ultra-mini'skirts?

I feel that I have to write this blog to reflect an interesting observation from last night. I finished my swimming lesson at around 10ish. Instead of walking home in the dark, I decided to take a bus. The bus departed from the sports centre (Surrey Sports Park) and went through the typical university route i.e. Manor Park (university accommodation) - University - Town Centre. At Manor Park, the bus driver picked up a group of 4 young girls, obviously university students, aged between 18 to 20 years. All of them were wearing stiletto and ‘ultra-mini’ skirts. What I mean by ‘ultra-mini' is the skirt length is just enough to cover the 'front-bits' and 'back bits'. Then, at the University, the bus driver picked up another group of young girls, around 5 or 6 of them. Interestingly, all of them were, again, wearing stiletto and ultra-mini skirts. Not that I was eavesdropping (at least, not intentionally), but I did overhear them saying that 'I told you that we are going to wear skirts' or something like that. It was apparent that these two groups of young girls know each. It also seemed that they had coordinated their outfits for the night out. Right at this moment, a question popped up in my head, 'is it a girl thing that they like to coordinate their outfits for a night out?' I cannot imagine a group of guys will do that, unless they were going out for a buck's party (I have seen a group of guys dressing up like golfers on a buck's night out). This coordination of outfits for a night out highlights an interesting, albeit not new, social phenomenon, namely group identity. This group of young girls seemed to feel the need to conform to the identity of their 'sisterhood' (the social group) by collectively wearing ultra-mini skirts. Obviously, peer pressure is a key factor for the conformation to group identity. Another factor can be self-confidence. I hypothesise that if you are confident about yourself, you are less likely to feel the need to conform to your sister- or brotherhood. I am sure some well-known scholars would have researched on this area. I am just too lazy to look up at the library databases. How about age? Do you think young people (e.g. teenagers) are more likely to succumb to group identity than 'mature' people (e.g. middle-aged or senior people)? I use the word 'mature' to signify life experiences, not necessarily old age. This question is based on my many observations at shopping centres. I have noticed that young people tend to wear the similar outfits as their friends as compared to ‘mature’ people. Maybe, I am wrong. I think group identity will be a very interesting research topic. Anyway, it's time for me to dash as I have some study to do before my day out with my flatmate. Maybe, I should coordinate with my flatmate and have ‘ultra-mini skirt’ day out?