That has to be Zuko's grandson, Zuko was slightly older than Aang and probably got married before Aang as well, and Aang's youngest child Tenzin is 50. Doesn't make the scene any less epic, it's still giving me chills. Watched it about 10 times so far.

For those wondering how metal is going to work in the next season, with it supposedly being the "element" for the avatar to master: Two things:

1. We don't actually know if Lin's bending was actually taken away. They just showed her fall, which she could've either faked, or have been the result of her protecting herself/secondary effect of energy bending. How could she have protected herself? Metal implant over her third eye or something. Just like chi blocking can't get through the metal suits, perhaps Amon's energybending/superchiblocking also can't. We still don't know the full details on how it works, after all.

2. It's possible that after Amon's defeat that everyone will get their bending back

3. Just because Lin can't metalbend doesn't mean she can't still teach Korra. Her knowledge is still there, she just wouldn't be able to actually do bending anymore. Don't forget the phrase "Those who can, do; those who can't, teach."