Here are a few horse competition available to Youth! Let me know if there are anymore I should include. Any type of riding, English, Western, Endurance, Ride and Tie, trick riding, ect.
AQHA Ranching Heritage Young Horse Development Program
Mustang Madness Competitions
Mustang Yearling Washington Youth http://box5476.temp.domains/~mustangy/
Teens and Oregon Mustangs http://www.teensandoregonmustangs.org