Is it just my SD or are all tweens this superficial????

So I took my stepdaughter school clothes shopping about two weeks ago and gave her a budget (we're not rich!!). She was fine the whole time. Actually she was pretty great and it was fun. I ended up buying her 8 shirts from her favorite stores and a new backpack that she loved. Yesterday, I picked her up from summer camp and she says to me that she needs more clothes for school. Then she goes on to say, "My Mom buys me at least 16 shirts when she takes me and you only bought me 8, I need more". WTF!!!! Was she seriously referring to the same mother that didn't even buy her a birthday gift last year, and even more, the same mother that took her birthday money and used it to bar hop!!! Yea, sure thing there, your MOM buys you 16, bull****!!!! That's not even the end of it!!! She started cheerleading and she needed tennis shoes for practice (they aren't allowed to wear their cheer shoes). So on a spare notice, and with little budget left (cheerleading isn't cheep to begin with), I bought her a pair of athletic shoes for her practices at target. As she was taking off her shoes she says, "I've never had a REAL pair of athletic shoes." So I look at her and respond with, the shoes I just bought you are athletic shoes. She has the nerve to tell me that they aren't REAL athletic shoes, they're target brand, and she NEEDS NIKES. WTF!!!! And it gets worse... She won't wear clothing from any stores other than the "brand" name stores. Even if it's the same shirt, she won't wear it unless it says the brand name. She may be thankful at the time when she receives something, however, she surely is not grateful for all she has, and that really ticks me off. I work my A** off and so does my husband to provide for our kids. So to have her be soo ungrateful just makes me angry. I don't even buy my BD brand name clothes. I buy from consignment sales with the occasional new article (if it's on sale). I'm annoyed, had to vent. Any advice??