They did said “80 years or so” and “around 80 years”, maybe they did their calculation and predicted that this year is likely the time that it happen. They did give a huge margin of when it will happen though.

According to Wikipedia:

In March or April 2023, it dimmed to magnitude 12.3. A similar dimming occurred in the year before the 1946 outburst, indicating that it will likely erupt between April and September 2024.

Novas can recur. Supernovas cannot