I saw this when I was around 8 years old, and I remember thinking it was great, so when Korra was announced, I rewatched it because I couldn't remember a lot of things. That was one of the best decisions I've ever taken. This show's story is so deep, so entertaining, fun, emotional...

How it goes back to previous avatars, previous events, how the story develops with every decision taken, the fighting, every character development, even the secondary characters...

Book 2( season 2) was just a masterpiece, if you feel a little unsure at first because it may seem childish, just wait for season 2, you won't see the show with the same eyes.

I can only imagine how this would be if it was at least PG-13, or maybe even R rated, because yeah, sometimes you can see that it was intented for kids, but still, you can watch it at any age and will have a good time.