I have only one objection. I suppose everyone has the "right to define themselves" and thus you can term yourself the "vicious babushka," but if anybody else called you "vicious" they'd have to deal with my teeth and claws.
Oddly, I'd feel better about "nefarious," "iniquitous," "barbarous," or even "Bad Babushka".
May I -- fondly --call you "Baba the Barbarian"?
There was a headline from Russia, some months back, about “Vicious Babushkas” doing something or other ... I think it was showing a bunch of homosexualist protesters the sort of respect and admiration they so richly deserve. Beat ‘em up with their purses, IIRC.