In the latest opinion poll from the most No-friendly pollster[1] 'Yes' is ahead in all age groups apart from the over 60s, where No is way ahead. If there is a No vote it seems likely to have been won by the old. This backs up the narrative from this article that Britishness is dying out in Scotland (of course, pensioners have also been frightened by scary stories about their pensions, and tend to be more small-c conservative, so it's not entirely an identity thing)
[1] YouGov. Different polling companies appear to have different systematic errors in their results, meaning that polls are spread fairly widely. This particular polling company has until recently been showing large leads for No. In their most recent poll the lead had been cut down to 6%, reflecting a feeling 'on the ground' that there's a genuine shift happening. Personally I am still totally unsure what result we'll get in two weeks (two weeks!)