Not a teacher.
Think about flying an airplane. You only have so much fuel. You leave point A, heading for a distant point B.
Early on in the trip, you have enough fuel to get to point B. You also have enough, in case of trouble, to turn around and go back to point A.
At some location this is no longer true. You have gone too far to have enough fuel to return to A. You must go to point B.
That is the point of no return. When you cross it, you are committed to reaching your destination.
Student or Learner