Getting a list in a derived class

So I've been trying to get this code to output the count of a list in a derived count but for some reason it always says the count is 0. I'm not entirely sure what I'm doing wrong. Is it jsut not possible? Help!

 public class ShipBehavior : MonoBehaviour 
  {
      public List<Vector3> position = new List<Vector3>();
  
      protected void Start () 
      {
          SetPoints();
      }
  
      protected void SetPoints ()
      {
          position.Add(new Vector3(-2f, -0.9f, -4.5f));
          position.Add(new Vector3(0f, -1.2f, -4.5f));
          position.Add(new Vector3(2f, -0.9f, -4.5f));
      }
  }
  
  
  public class BarrelParent : ShipBehavior
  {
      void Start ()
      {
          InvokeRepeating("Spawn", 2, 1.0f);
      }
  
      void Spawn ()
      {
          //outputs as 0
          Debug.Log(position.Count.ToString());
      }
  }