Would it be considered normal to want to kill people that make my life miserable instead of myself?

Well, it depends: In extremely painful situations, feelings like this can certainly come up. But how well you contain them (without acting on them) is very important also. It's also important to know how easily and often you go to this place. These responses can also be part of various mental health conditions that need care. Your asking indicates your concern, so i suggest consulting with a psychiatrist.