When was Elizabeth Bennett born in the book Pride and Prejudice?

Jane Austen, like many writers of the time, chose to be vague about the specific date in which the novel is set. So there is no way to really answer this. However, it is at some point between the Napoleonic wars, so Elizabeth must have been born a little before that. Keep in mind that she was age 20 at the start of the novel, this giving some clue.