@ChonChin Just as ArieSun said, plus it gives all the more reasons to why she's against the family's tradition.
Yes, some kids, e.g. her brother know that the family traditions are wrong, but "having been born and raised in a peaceful place, devoid of violence" (as far as it's told from her mentioning about her prev life) raises the possibility cuz well, I doubt the original novel gives many details about the family so she might not know that they kill those who fail the "special tests"