Help getting over someone riding my horse
So, I own a wonderful 5yr gelding. Broke him myself last year, got him from a not so great home. I dont trust anyone with this horse, I dont care if people hop on my mare, but no one is to touch my gelding. ever. So Im doing a green horse/green rider class at the college and a lady at my riding group told me the trainer will have everyone switch horses. when she said this im screaming in my head "NO NO NO NO NO NO NO!" I can understand having people ride other horses for experience but I dont know anything about these people! I watched their horses to see if I could get a feel for the people, the horses were just running wild in the pens without anyone in there and they were soooo antsy. My guy, who is like spook-tastic looked like an old pro next to them. Just did not give me a good feeling.
Am I wrong to feel like this? Maybe if he had a few more years and I knew the person Id feel better. And how do I get over this?