Why am I so mean and have a attitude?

Ever since I was little,I was mean. I would have attitudes and get mad so quickly. I would always bite people or do whatever. So as I was growing up my attitude and mind set got worst.Now that im 15 it has been worst.I get attitudes with my parents which I know its bad but I cant help it, it just comes out of my mouth.I get mad real easily to the point iwill shut down and have a idc attitude.I dont know why I have a attitude but every day its ruining mylife and I need to fix it quick before I am the person I always said I wouldnt be. People always tell me I have a attitude but I dont care because people treat me like this so .. idk.