No she just has a curse that is trying to make her the main character. Just think of the curse as the readers comments on her actions and expectations.
Oh lol when she said that it’s gonna follow the same plot line made me think she is one and also the fact that she’s acting less like the main protagonist from the book also evidence that she is one really made me think so.
Meaning as plot i think thats what the curse revealed to her? Plus her acting different is even because of the mc's actions like the butterfly effect or because of the curse or even she was like that from the beginning.
Wait... is yuri also a reincarnator?