How do I load a scene when my List is empty?

     void Start()
     {
 
         unansweredQuestions = questions.ToList<Questions>();
 
         if (unansweredQuestions == null || unansweredQuestions.Count == 0)
         {
             SceneManager.LoadScene(0);
         }
 }

I have this Code where I reload the scene every time I click a button, and it takes one random thing from the List, but after it's taken all of them out of the list, it fills it up again with this piece of code, How do I make it so, that when I start the scene, it fills up the list once, and then loads scene (0)?

Something like this but I'm not sure what condition to put on the unansweredQuestions = questions.ToList();

     unansweredQuestions = questions.ToList<Questions>();

     if (unansweredQuestions == null || unansweredQuestions.Count == 0)
     {
         SceneManager.LoadScene(0);
     }