These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
She wanted to get discovered and tell someone about her power. If she didn't, she could just have reversed it.
She knows exactly what to say to people to get them to do what she wants. If she makes a mistake, she can just redo it. She demonstrates this in very yandere ways to Joe Chip: I could have married you if I wanted to.
But at that point, aren't you just some sort of alien creepy chameleon? Are you even yourself anymore, when you just reflect back at people what they want?
So maybe that's why Conley decided to talk to someone about her power after all, and revert the future where she married Chip. Consciously not using her power all the time to do the "right" things, try to be herself instead.
Whereupon they all (minus Runciter (?)) die in an accident, which she waited too long to revert. She finds she can't revert past the accident.
Then Joe Chip dies. Yes, Joe. Conley reverts it, but finds that no matter how many times she does, one of them dies. Because now they are in a universe belonging to Jory, and when he has to eat, he eats! She settles on a future where her rival for Joe's affection, Wendy Wright, dies.
Then they keep dying one by one. Conley keeps saving Joe, making agonizing decisions about who to let die in his stead. Guilty about this, and especially about Wendy, she lies to Joe and says her power has stopped working entirely.
In the end it's just her and Joe left, and Joe thinks she's been orchestrating the killings. Then she dies, rather than revert her own decay because she understands now that there's only Joe left to die, and if she doesn't die he will.