How we cite our quotes:
I will be brave, thought Coraline. No I am brave. (5.98)
By the end of the story, being brave is a huge part of Coraline's identity. This seems to be the moment when she realizes this, too.
Sometimes Coraline would forget who she was while she was daydreaming that she was exploring the Arctic, or the Amazon rain forest, or Darkest Africa, and it was not until someone tapped her on the shoulder or said her name that Coraline would come back from a million miles away with a start, and all in a fraction of a second have to remember who she was, and what her name was, and that she was even there at all. (6.3)
Neil Gaiman describes the power of imagination perfectly here. When Coraline is daydreaming, her dreams are so vivid that she can be transported completely out of herself; she even forgets her own name (join the club!).
(Was there an other Coraline? No, she realized, there wasn't. There was just her.) (6.5)
The short sentences help to emphasize the weight of Coraline's realization here. For better or worse, she's the only Coraline. Identity is unique – no two people can be the same (including Coraline's real mother and her other mother).