Feeling Weak and Jealous of My Cousin

I always liked feeling and imagining that I'm strong but every time I feel and act that way everyone seems to always prove me wrong that I'm strong. I feel that Sarah my cousin will always be stronger than all of us. she is very intimidating to the point that nobody can say the truth about how she is. I don't like her because she always wants to find out what we are up to, she talks to family members, only the ones she like that have the role of superiority in each family (cousins). I'm jealous of her because she is strong, outgoing, and cool, and my youngest sister loves her and it's that I feel that my sister loves her because I see how she is every time Sarah comes to visit. I hate Sarah but everyone seems to like her. I want to disappear and start a new life elsewhere. Act differently and see if that will help me find peace and happiness. I don't want to feel jealous and I don't want to be around people that look down on me, I hate that but that is how the world has been for a long time. I'm very quiet, awkward, and have a social anxiety disorder, I can't hold a job for a year or less. I'm very sensitive, I want to satisfy everyone, I can't say no, I can't handle angry people, I wanted to always help my family but it seems that they are helping and my problem. I'm a 31-year-old woman that still lives with my mom, I never left home so I am not independent, unfortunately, I'm dependent on everyone else. I'm a worthless human being that is walking in this earth. I think God should've me cancer and cure a cancer person because they have a better change to live life better than I can.