The way it works in the mom column is that you are mom, grandmom and then great-grandmom. But in the other column, the aunt column, you go straight from aunt to great-aunt. For some of us, that brings up images not far removed from Miss Havisham (Great Expectations… try to remember your high school English class).
So I would like to propose that we re-invent the order for aunties. It should now go: aunt, grand-aunt, and then great-aunt. I would love to be a grand-aunt. It just sounds like so much more fun.