Question: what is the time period of avatar the last airbender?
Answer: Aang dies at age 166, which would be around 1905–1906. The world of Korra appears to be in the 1920s. Since the world of Korra is stated to take place roughly 70 years after the war, the show would begin around 1923, meaning the technology was right for the timeframe, and Korra would be her canon age of 17.