How to dress unique, vintage, but not too out of the ordinary?

Well, I was always the girl in school who would just wear a plain old t shirt with a plain old pair of jeans and a plain old hoodie everyday at school... My clothes weren't ugly... But they were just so dull... My two best friends, one of them is rich and has so much nice brand name stuff and some really cute tops and so many jeans, my other friend has SO much clothes, yet hers aren't all the fancy brand names and she puts together all her clothes and makes some funky, unique, outlandish, and yet pretty spiff looking outfits... Now, her goal is always to look different, even if it meant wearing the strangest stuff. Now, I don't want to be quite like her, but this year, I do want to be different and create my own style, and I'm really into vintage stuff and all my friends know how much I like old music and I also have a vintage looking bedroom... Anyways, I notice how modern-y everyone dresses, so I'm like, well I can stand out by looking cute and vintage thrifty... Now some vintage outfits I've seen are like WOOAAAHHHH, like, I don't want to look THAT old... But I still just want that kind of thrifty touch... Also, I'm only 13! So where would be some good places for me to shop? I fit extra small in most stores but only in shirts. I'm really short with pretty scrawny legs so I have to wear kids jeans still. But I can wear skirts from adult stores too and probably dresses. Also , what jewelry would be cute? I know Forever21 has really cute vintage jewelry, anywhere else?