Your parents and siblings are huge disappointments! No kid should be the target for criticism and harassment in her own home. Your parents should be ashamed of themselves for tolerating the way your sisters treat you and for joining in the bullying. I don’t really have enough information to analyze your family. My only guess is that your siblings are jealous of you. Unable to match your gifts, they put you down to feel better about themselves. Sometimes parents try to even out their kids’ abilities by putting a gifted kid down. They think they are preventing the other kids from feeling bad. As I said, I don’t have enough information to understand what’s going on so those are only guesses.
I do know this: Not every kid gets the family they deserve. Not every kid is loved, protected, nurtured and supported by their family as they should be. It’s sad and frustrating but it’s the truth. Some kids just don’t get a fair deal. But that doesn’t have to determine what happens in your life. You have a gift. Don’t let anyone take your voice away from you. It’s probably your ticket to a good college and to a different life. Work hard on your music. Write songs to help yourself with the pain. Get yourself involved with a chorus or choir or musical theatre or a band. Such groups will put you in contact with people who share your interests and who support each other is making beautiful sounds in the world. You may meet older people who can mentor you and help you on your way.
In 3 short years, you’ll be able to leave home to go to college. Work hard in school and in activities that support your music so you can apply for a music scholarship. The quality of your life doesn’t have to be determined by your family. You can set your own path and make a future that is filled with supportive people who love you for who you are.
I wish you well.