Horse people please help me out!!!

When I was little we had a horse farm and boarded horses. One day, me, my dad, and my sister went walking in the pasture to the pond to check on something. There were about 4 horses that came up to us. We petted and loved on them. They were familiar with us. Then, they ended up (out of nowhere it happened so fast) hemming us against the fence and had their butts pointed at us. We were so young that we didn’t understand. My dad said “ugh, I don’t like this, we better try to get out” and he shoved me and my sister through the horses then we waited for him to come out. This was literally like 30 years ago. I still never knew why they did this. I’m wondering if they were going to all kick us or something. What do you think?