Help me deal with my life?

I am a 4'11 Indian girl with black hair and medium dark skin. I am the shortest one in my family and I hate it. What can I do to look tall? I am taller than my mom and my dad is around 5'5. I am 15 and almost 16 in about 3 months. I know I stopped growing because I haven't grew at all since 7th grade. I never ate good in my life and I felt like I never had a growth spurt. I feel ashamed to go out in public or to a Indian party. I don't even want to celebrate my 16th birthday because I am so short. I make all high A's in school and I have no problem with my studies. I have really bad posture and everyone makes fun of me for that. I feel like a failure and I feel like killing myself. How can I improve my posture? I feel like everyone is better than me. My cousin is better than me at everything and I am really hating her. When we were little, we used to love each other and we used to play all the time. Now she thinks she is better than me and treats me like dirt. She is better at me in playing the violin, she is a level higher than me in Kumon, she sings really well and the singing teacher loves her, she does things really fast, she's filthy rich, everyone in my family loves her, she's my height, she's smarter than me, and she did all these competitions and won awards. She's 13 and going to be in 8th grade!! I am going to go in the 10th grade. She skipped a grade, and I did to, but then we moved and I had to redo a grade. I feel like a failure and I feel like dying. I want to be a medical doctor when I get older. I won't commit suicide, I know better than that. I want to fix my life, but I don't know how. Compared to all the other Asians I hang out with, I am a loser. Please don't write rude comments or anything inappropriate, I am already going through a lot. Thanksx