I am really sorry. I have to say, that I live in Northern Va, and find that if you are not on your traditional hunter/jumper type horse, they are not very accepting. I am an adult, used to be in the H/j world, and frankly, am glad to leave it. Too many spoiled brats (adults and kids) for my taste.
First tho, you should not have stuck out your tongue. That really just baited them and gave them an "excuse" ( in their very small brains) to act up.
I am pretty sure there is some jealousy there also.
However, I would recommend that an adult (mom, gram, 4-h leader) talk to the people in charge of the shows. This behavior is very dangerous for everyone there, as well as the animals. Sorry to say, but I think that if an adult talks to another adult you may get better results.
I do like the caution tape idea too-that one is pretty good, or just the survey tape I think they call it at Lowes or Homedepot-orange or pink-will do the same thing. We use it to mark trails.
I sure hope that there are nice sensible kids like you at the barn in Purcellville I am bringing my horse home to this winter.....they also have gaiteds, and they are not that common in those parts......
In the meantime-go and have fun at the fun show-that is what they are for, and don;t let these girls get to you.
Signature undergoing edits. Please standby.......