Honestly the writing is terrible. You care enough about the kid to get them a maid but don't care enough to make sure the right person showed up? Or even tell the kid who the right person is? Absolutely idiotic. Also how has she not been caught by now? She literally wears the same outfit all throughout the story, and the news reporter says there were a lot of witnesses that saw her going in and out of the house.
The concept is fun
(although beaten to death at this point imo, seen too many of these copy and paste "oh no she's not the right person dun dun duuun!") the execution was atrocious. Also what's up with the "I will stalk this boy and learn everything about him in an attempt to get him to love me instead of just talking to him, despite the fact that I am clearly attractive and could easily convince him to date me!" At this point she just likes killing people in a contrived and illogical way that is likely to get her caught, which is dumb.