GotaDun, she wants to show 4-h. 4-h is for youth, any breed, and any skill level. We should never discourage a 4-Her from trying it out. There is nothing wrong with saying "you probably won't qualify for the world show", but we should NEVER discourage a 4-H kid from trying something out. As a 4-H leader, I know that very few gaming horses get a chance to slow down, and when they do, they're usually a lot happier.
I am a 4-H parent, of a kid who took a finished barrel horse and turned her into a 4-H level WP horse. I am a 4-H leader, and I am a riding instructor who gives lessons to several 4-H kids. Maybe I'm a little opinionated in this area, but why pigeon hole kids and tell them their horse might not be able to do it. LET THEM TRY!