My expectations seem to have been misplaced - MC is truly going for the offensive "revenge" instead of defensive "survival".
At this point, I wonder if I missed anything, but I am wondering whether something set the "original" Mielle off (the "current" Mielle being, as indicated by MC, "a child yet to become mature and wise"), possibly even the behavior of the "original" MC (what irony that would be). I find it difficult to cheer for the current MC as she is doing the exact same thing the original Mielle was: bullying the other girl every single chance she gets. She is motivated, for sure, but her actions lack "justification" at this point, more of "an eye for an eye" (forgetting it "makes the whole world blind"), since current Mielle has yet to do something to warrant such hostility. Basically, the girls' roles have been reversed, which I find boring as it feels like the same story happening twice except the "product labels" have been swapped for the second run.
Basically, I sympathize with the current Mielle far more, although not as much as the original MC...yet.
All of this does resemble an hourglass, I suppose: its two halves fulfill the same role over and over in turns; regardless of how many times you flip it over, nothing about the process changes, it merely repeats itself without the slightest deviation.
