Years ago, I volunteered at a local elementary school for a school year. My job was to help some of the students who were falling behind with their grades with their classwork. It was a worthwhile volunteer job for me.
When I worked with the kids, who were in the third grade at the time, I decided not to require them to call me "Mr. Brown." Instead, I let them just call me, "Mike."
The reason was because I felt that the young students would respect me just as much if I let them call me Mike as they would if I made them call me Mr. Brown.
Of course, if you work with children and you want them to call you Mr. or Mrs. Such-and-Such and not call you by your first name, then that's fine. You have that right.
But I was fine with them just calling me by my first name.