CLOTHES!!!!! I want a change...but not a big one!?

okay, so this is my first year of highschool, and i am a tomboy. The one always wearing sweatpants and short. Now, i wanna wear jeans and skirts! lol, but i can't spend to much on clothes. I also don't want anyone to judge me...i really got the confidence from watching icarly, (lol i know kiddy show) and the way Sam dresses inspired me :) And, i went one week to a camp, and i wore fitted clothes and guys actually liked me...so i would like that to happen again! But, of course i ain't the skinniest person alive...im 5'2 and 133 pounds. And, wear 5 or 6 in jeans. Where should i shop? And, my mom said i can spend 120 bucks (cheap mom) and i want some jeans and hopefully 2 skirts. I have stores like Aeropostale, American Eagle, Old Navy, and Rue 21. I would like doing the layered look, and just plain shirts, and leggings...is this possible with the money im getting aloud to use? and would people look at me weird if i changed? THANKS :)