Okay, sorry, my mistake. For some reason, I thought headers had to be 12 and over, but they actually have to be at least 13. Guess this is my reminder to re-read my rule book
CL-030 DRIVING CLASS GENERAL RULES
H. 4. Headers: A header is an appropriately attired (show
attire or unlettered smockwith suitable footwear) capable
person 13 years of age or over. This attendant shall
take NO action that will affect the performance of any
Miniature Horse. Only one header is allowed per
horse. The header must not have a whip and shall
remain at least two (2) paces distant from the head of
the horse when the judge is inspecting the horse, and
at all other times unless assistance in controlling the
horse is needed.Adult (19 years of age or older) headers
are mandatory for all youth drivers and optional
for all other drivers.