Ride out west with Jonathan's brother

I have to laugh at this story, because it just shows that I know nothing about horses! So, me and Jonathan went on a ride out west of Utah Lake with Jonathan's brother Michael, on some horses that they had been breaking. Anyway, they put me on this horse that had been broke but they were still working with it. Let me tell you what, I was scared to get on that thing but I didn't say a word and I got on it anyway! If they wouldn't have kept saying "which one we going to put her on" and "yeah, he will probably be the best", I probably wouldn't have thought twice about getting on the horse they were putting me on, but they were making it sound like all these horses were newbies, and here they are going to put a city girl on it! Anyway, the ride went really well, and I didn't have any problems with the horse until we were almost back to the truck...the horse started laying down and Michael is yelling at me to get off, and I had never seen Jonathan move so quick in his life off his horse running over to me. I didn't see a problem, but apparently they were worried about the horse rolling over onto it's back with me still on it since I didn't know to get off the thing when it starts laying down. So, that's why we never let the city girl ride a greenie horse again!