When was Yue's life?

The seven laws "happy life" refer to people over 50 years old.

I'm over 50 years old and I've struggled for half my life. I don't know when spring will come, but the grass grows and the warbler flies.

I am a mortal, not a fairy. I often ask everything in the sky. Why can I only have the reincarnation of spring, but I can't be a teenager again?