I don't like it either OP. But I don't have an answer.
'Auntie AllPast' (my parents' solution for me and my brother's to use with family friends) - no-one does that these days.
Plain 'AllPast' - too familiar. I am not their friend. (Neither am I the friend of the idiots who call me from Orange or whatever. and address me as 'All'
.)
Mrs Years - horrible. I never go by Mrs anyway. I'm a Dr professionally, but wouldn't ask kids to call me that, they'd think I was a loon. The father of a friend of my brother's was a doctor (medical, not academic like me) and insisted on being called Dr X socially rather than say Mr X by younger people, or Fred by contemporaries. Everyone thought he was a loon!
'Ms Years' - weird when I'm not their teacher.
I've got used to them calling me 'Allpast' but don't really like it.