Time Travel and Rebirth, the System Allows Me to Become an Immortal Quickly

I accidentally traveled through time and was reborn, and unexpectedly got a cheating system that urged me to cultivate immortality. Immortality will be my motivation! Everything else is false! I thought my life was about to be cheated, but I encountered troubles and traps again and again. People in this world are really old and mean. Finally, I accidentally discovered that the system is... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.