My cousin 1 ups me in everything?

A I really need help and advice how to not be so down about myself.
My cousin has 1 upped me in everything for years. And she gets everything she wants since her family is quite wealthy compared to my family. For example I wanted a computer when I was 13 and I told her about how much I wanted one and I hoped I was getting one for christmas and when christmas hit she got one. It has continued now she is 2 years younger than me. She's in now a senior in a private high school and I'm a freshman in community college. I know she's going to get into a better college and that depresses me. She's always had nice clothes, perfect teeth, and iphones and computers She can drive while I can't and she has her own car which I don't have. She has many friends while I have barely 2. Everything I have ever wanted. She's prettier and I don't feel I can succeeded at anything because i'm always put in her shadow and she's younger then me. I have always had messed up teeth and I've never felt pretty while smiling. My family can't afford braces which really sucks and I need a job but my mom won't let me get one till I finish school because I have to babysit my brother at all hours. My life is going no where. I feel ugly, and just an outcast from my family. I often hurt and mutilate myself because of this, I just don't feel like I can get anywhere or make anyone proud. I really need advice or motivation to do something about myself. I have no one to turn to.

I know you feel, i have 5 year old cousin, and feel like strangling him with no end. My suggestion, make her feel bad in any why you can find. And if someone say's your acting immature, tell them to screw off.