Can you do the liberty class at the fair if you just ride walk trot?

i really want to do liberty at our county fair(because my grandpa says we can not do it, that my horse will not be good at it so i want to prove him wrong), but i have had a few people tell me that you can only do it if you are walk/trot/canter, so i asked my barn owner (she use to be one of the advisors in the 4-h group that rode out of our barn but has since been disbanded, long story) and she said she thinks you can because its based on the horse not the rider. then i asked my 4-h advisor and she said she doesn't know but she would get back with me when she did. i think she forgot though, but on tuesday im going up to our 4-h extension office to ask and get the correct paper work, since its not a 4-h week this week. so my real question is can you do liberty if you are just walk/trot. no nasty answers please