Help! My mom wants to send me to a different high school that I don't want?

I'm going to high school next year and at first my mom wanted to send me to another high school which was not my district because it was a better school. And it is. But now she's refusing to send me there and I'm not completely sure why but I have a suspicion that my stepdad refused to send me there. Because my ex-stepbrother (looong story) goes there, and he's a freshman there right now. My mom made the excuse that they couldn't transport me there. But it would only take 15 mins to bike there. And now I'm really mad at her because it's a much better school. The one in my district is basically a sports school and I want to be a writer when I grow up. What can I say to convince her????????