the tsc eldest daughter curse goes crazy actually.
ella herondale: killed by a demon at 14
barbara lightwood: killed by a demon plague at 24
anna lightwood: alive and well but also not quite a daughter in the truest sense of the word
aria wrayburn: killed by demons at 19
amatis graymark: was used as a pawn by both valentine and his son, forced to divorce the only man she ever loved and watch him marry another, forced to become the first of sebastian's endarkened, killed at 40
rebecca lewis: alive and well but also just a mundane
helen blackthorn: exiled for having faerie blood and forced to spend 5 of the most important and trying years of her siblings' childhoods apart from them
amatis, rebecca, and helen.. even tho they all at least lived longer, they each lost a parent young and had to step in for their younger siblings, only for downworlder blood to cause fissures in their families in one way or another. the rest of them--ella, barbara, aria--were also separated from their siblings at a young age, only it was their own deaths that caused it, or, in anna's case, the death of her only sibling.
and idk i just think it's interesting and so sad that whether by death or other immutable factors, each girl ends up alone or apart. (provided i haven't forgotten any eldest daughter outliers)