There's a whole methodology for these things in other cultures. In the part of India my family is from originally, you get called "sister" if you're the same age, "mother" if you're a little older, and "grandmother" if you're older still.
However, if it's across class lines, you get called "mother" even if you're much younger -- the gardener, a 70somthing man, would call me "mother" when I was six years old.
I appreciate a little more formal courtesy that most people seem to like. Sir, Mister, Ma'am, Ms., etc. It's so easy to encroach on other people's time, space, and attention. Maybe it helps a little to make an effort at courtesy and maintaining interpersonal boundaries.
I would certainly not persist in calling someone by a title if they requested otherwise!