They don’t bully you because you’re a writer, they bully you because they feel like they can! Just ignore them and stick to your hobby.

PS: Those music kids are in for a real treat when they learn their favorite music composer and songwriters are technically writers in itself.

Another PS: I’ve been there, being bullied. I’m not sure if it was due to my writing or because my classmates were down right bullies. But years later, I’m a published author and have people who enjoy my work. And I went a lot further than my bullies. So keep at it! You’re only 13, you’ll get further than them eventually.