Ok Me and my brother are always fighting, Im 14 and he's 9. He just always starts something with me!?

And we end up fighting, not a fist fight but a lot of hollering! I try to tell my parents about it but they don't understand. They say i have to be the Mature one, and I try to be but he's so annoying! He doesn't respect me, and has a smart Mouth! If you guys can help me in anyway please do so!!!!!! Thank You!