Based on what is written, I see two factors at work here:
- Child with perfectionism issues dealing with not being perfect.
- Child with lack of experience with anything challenging finding something challenging.
And, having been through something similar at an earlier age with my own DD8, here's how we handled it in our home:
- Focused on teaching writing as a process, which does not have to be (and should not be) perfect the first time through. We introduced word processing at a very early stage, because the ease of editing made this point easy to convey. If you have to scratch out on paper, it looks ugly, which is not something that flies with a perfectionist, and rewriting is a tedious chore.
- Tried to encourage the idea of writing for fun, by encouraging more free expression. Our DD has a very silly sense of humor, so we encouraged her to write more humorous fiction. And then we were careful to point out which stories we particularly enjoyed, and what we liked about them.
