Good luck with the meeting bk! I'm glad you are advocating for a reasonable challenge, I agree with everything you are saying about inadequate challenges leading to underachieving in the future.
I have been working with both the kids on this.
When DD5 was so upset about making mistakes and was about to quit, I asked her why is it that every pencil in the world has an eraser on the top. She thought for a minute and then started laughing. That's right, I said, If no one ever made a mistake the pencil making company would go out of business and a whole lot of good people would lose their jobs!
It seemed to do the trick.
Marching onward in battles against perfectionism.

Neato