No I don't think she will because if the writers were going to kill off one of the main characters they would want to suprise bạn make it happen from nowhere so bạn dont expect it.
She could die in the flash sideways.. that doesn't mean she is dead on the island. I don't know how they are going to connect the 2004 lives of the passengers with the 2007 (on the island) lives. Can't wait to find out!