So in the last season review nick released there is a scene where an elderly fire nation woman is looking down at Korra, asking "Do you know who you are?". My first thought was "the new fire lady", next thought was "Too old to be Zuko's daughter!". Well... not really. Think about Lin Beifong who is 50 years old, daughter of the youngest member of the group who wasn't shown having any love interests during the series. Zuko was the eldest of the group and was heavily involved with Mai, and marriage, atleast in my eyes, was assumed. So, young marriage, young child, could mean their daughter is easily 60. Plus if Iroh is the son of Zukos eldest daughter's son, and he is, let's say 28, It could also be very easily possible his mother is 60 or older. So! Anyway my point is I see it as a possibility, especially considering the lack of Zuko and his family in the series so far.
It would be so much easier if I could just show you a picture of the woman of which I speak, but sadly that would be against site policy so follow this link and go to 1:22.
Let me hear your thoughts!