Is this excerpt OK for a 15 year old writer?

If I'd written something like this when I was 15, I would probably still be proud of it now, so yes, it's good for 15. You still have a few things to learn about writing... such as it not being a good idea to respond to insults with other insults. (I would probably have reacted the same way when I was 15. That doesn't make it right.)