On that...spoilers:end of spoilers
I think that is part of what Morraine's conversation with Nyneave is about. By getting her age she is able to dismiss her as a possibility. It isn't well highlighted in the show, but in the books Morraine has the exact date of birth for the person she is looking for - the rest of the Two Rivers group is supposed to have been born over a span of less than a week. Pair that with no real records and any of the rest become a possibility. As far as the source is concerned, one of the episode titles is Saidin, Saidar, Stone, so I think two halves will come up later.