Is it weird as like a 15 year old to shop places that my 20 year old sister shops at?

I have always dressed more maturely, and so I shop more at places that like 20somethings would shop at than like people my age would. Idk like I guess everyone at my school just goes to hollister and aeropostale, but I go to Forever 21, Charlotte Russe, Gap, Old Navy, and ik Wet Seal is for teens but I go there too, and oh yeah I LOVE New York & Company..... oh and Francesca's Collections. I always see like older people there and sometimes, I just feel young walking into those stores, but thats the kind of clothes that I really like. Is it weird for me to shop at these places?