From what we've seen of her, did it seem that any of the versions was aware of the others? Or of the Doctor? I realize that there really was no reason for the subject to arise--well, maybe at the grave. Duh. But no other sign of recognition except for Clara's repeating Oswin's words. Or maybe that would be that Oswin's repeats Clara's, since Clara was "first" chronologically. Apparently.
Either she IS aware of her repeating appearance all along, she is UNaware until the moment of death, or she is totally unaware and there's something else going on that allows her to repeat final words without knowledge of that fact.
It was left deliberately ambiguous. I got an impression it was a subconscious thing, but it was still an intentional connection.
I don't think we've witnessed her death, though, since that would be too much like River Song.