Tenzin is 51 and judging from the family photo we got last episode, I think it’s safe to say that both Bumi and Kya are also in their 50s, Bumi probably towards the later 50s. 

But as for exact age, until we know a bit more about what happened between The Search and Aang’s death in 153 ASC.

Unless I’m wrong, in which case – someone will correct me.

-Da7e-