The way you said it was not put into good word choice.
Saying "Oh I've never seen you pitch, I doubt yours are perfect!" is horrible word choice, you are telling me that I think I'm perfect when I don't ever say that, I often say that I am no expert. No point in saying that, a better idea would be:
2. Ask me what my mechanics are like
3. State that you would like to see my mechanics
This was not the way to go about it.