This is a somewhat current problem of mine - I took a gap year, was an English teacher/youth worker, travelled, saw and did a lot of stuff, and was pretty independent. It required me to mature. Then I came back, and it seemed like nothing had changed for some of my friends. I just cant run around and act immature like I did before, it feels kinda wrong - like Im somehow taking everything I experienced/learned in that year and chucking it out the window.
EDIT: Im turning 21 though, so I dont think this should be an issue at 13! Either your current situation at home/school requires you to be mature (I honestly cant say since I dont know you, Im just suggesting it) or maybe you should loosen up a bit?