Even at the age of four she was considered smart. She remembers her mother telling her that she had a gift, that she would grow up to be something special.
You have potential. You can be whatever you want to be.
She's grown up knowing she's smart, but for most of her life it was only a book kind of smart, the ability to learn and memorise and recite facts and figures.
Then the war came, and she knew she had to be a different kind of smart. The kind of smart that keeps you alive in these situations.
She's smart enough to know who's winning, and that's why, out of the three of them, she's the only one left.