Honestly this could just be speaking to some niche desire to have a traditionally femme but still awful name as though it were assigned to you by your parents. Being like "Please, call me Millie, my real name is Mildred (ugh)" definitely lends an air of legitimacy to the whole thing. And it's a classic real world experience of many cis women.

That's just a guess though, more power to her either way, maybe she just thinks Mildred is a rad name. At the end of the day my opinion means jack and/or shit so do what you want.