Yup, I know how you feel. I have a palomino who I show. We finally got her pony carded this year though (she's a horse with long feet, and a pony right after the farrier comes) so we actually did really well in the large division last weekend. As others have said, the hunter world is dominated by TBs and WBs who tend to be chestnut, bay, black, and grey. Ponies fortunately tend to be a bit more colorful though. Your mare looks like a great mover so I'm sure you'll do well!
This is my mare (who just recently decided it's okay to actually listen to me, drop her head, and stop running around like a giraffe haha) if you're interested :)