So I have never read any of the books but am up-to-date with Season 4 of Game of Thrones TV show. I have a few questions about the concept of a super-long winter within the show. I hope the readers of the books will be able to better answer this if I have missed some points already discussed in the show:
How long does the summer last? How long does the winter last? Multiple years? Decades?
Is it right to suppose that none of the Stark kids have seen winter at all?
As far as the latest book goes, has winter already started in Westeros in the latest book? Or do we know when it will start?