Should Kids Call Adults By Their First Name?

Throughout my life, I've been told to call adults multiple things, Mr., Mrs., Mizz, or by their first name. As I was a pre-teen I called my employeer by her first name, I was told by my father that I should call adults by their last name, and not by their first. So I attempted to call R. by her last name, and she told me "C., you can call me by my first name, if you call me by my last name you remind me of my monther-in-law." So I reminded calling R., by her first name, and I still do. My minister from my old town I remember being a 7 year old, an going up to him and saying "Mr. Reverend R." and Elven asked me to call him Elven, but then we have friends that they perfer to be called Mr. and Mrs., which I started calling them Mr. and Mrs. Since I moved up to MA, I went into the library and I've been calling Mrs. T., Mrs. T, a couple months into volunteering at the library, she asked me to call her S. I responded "Okay, but if you don't mind, I would perfer if I could call you Mrs. T., you have a way to connect with kids, but still show authority." Mrs. T. said that that was alright, but now I want to hear from the adults and kids that read this blog.

Do you think that kids should be allowed to call adults by their first name?