Why does my mom think im so evil and mean?

Ok so im a 14 year old girl, and my mom always tells me how evil and vindictive I am. It actually makes me laugh when she says this hahah. Okay, so like she never sees anything wrong in what my older brother does, but when I do something, i'm all of a sudden evil? LOL, like today in the car, me and my older brother (he's 15) were arguing about something, and he told me to shut the **** up and he said it super loud enough for my mom to hear it, but of course she didn't say anything. So then we continued out arguement, and I was really pissed off still that he told me to shut the fuuckk, so I got directly in his face and yelled in his ear, "DON'T YOU EVER IN YOUR MISERABLE LIFE EVER TELL ME TO SHUT THE FUUCKK UP AGAIN YOU STUPID PIECE OF SHIIT." And then my mom pulled over, and told me to get out of the car! But I just sat there and didn't move and she just yelled at me the whole way home. Like I honestly don't give a shiiit about what my family thinks or says about me. I don't act like this to people at school bcos, ppl there are actually nice to me, so I return the favor. So that's why I have a lot of friends. I see it as an eye for an eye. They treat me like shiiit, so I treat them like shiiit. My mom NEVER sees anything wrong in anyone but ME. She constantly says how evil I am, and to be honest, i don't give a flying ****** what she thinks. I am not evil at all. They just give me a reason to not like them. They all gang up on me, and accuse me for my wrongs and never find anything wrong in their shittty, no good lives. My brother is playing HS bball and he said he wants to be drafted by UCLA. So every time he pisses me off or when we get into an argument, I just tell him that he will never amount to anything in life, and that UCLA would never want someone that horrible at their school and that I hope he fails in everything he tries at. Then my mom calls me evil and wicked? How is this evil? I'm just saying what I feel! Freedom of speech/thought! This is why I LOVE going to school. Because I actually like people there and they like me. So yeah, how am I wicked in any way? Kthanks!