Our instructor recently took us on our first trail ride, along with another mother and her two children, and the instructor's teenaged daughter. After a long trip, in which the trailer required some repair work with the horses in it, we arrived at the destination. I noticed that the horse that I have been using, and was to ride that day, seemed quite agitated, and was rubbing against, sometimes climbing the trailer she was tied to. She also attempted to roll several times. This behavior continued after she was tacked up. I asked my instructor if she was likely to try to roll when I mounted her, and she replied that the horse would only roll if I thought about her rolling (?) and that she was just irritated by flies. I did some deep breathing, and mounted the horse (stupid!), only to have her roll almost immediately. I did a superman jump off her back, and luckily escaped with only scrapes and bruises. I was immediately scolded and told that this was my fault due to worrying about rolling prior to mounting. She had me remount, and had to smack the horse to keep it from rolling again. I switched horses with her daughter, a much more experienced rider, and the horse tried to roll with her too. I was then told that I had taught the horse a bad habit because it succeeded in rolling with me on its back. I replied that I would happily have stopped it if I had known how! I was able to successfully ride the other horse during the trail ride, even though it was considered an "intermediate" horse, and I am a beginner.
My question after this long story is: Did my nervousness about rolling cause the horse to roll? I would not have thought about it if I hadn't seen the horse's agitation prior to the ride. I am not sure if I want to climb back on a horse if this is the case, because I am sure to be at least a little nervous after this experience! Thanks!