Character Select script issues

Hi all I've been working on a game and needed a solution to have a character selection screen. I went to youtube and have been watching and learning alot especially from GamesPlusJames and N3K EN

Here is the tutorial I followed. https://www.youtube.com/watch?v=IFTjcPvCZaM&t=1144s

The only issue is Unity Crashes every time i run the script and at a certain point the scene freezes when launched.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine.SceneManagement;
 using UnityEngine;
 
 public class CharacterSelection : MonoBehaviour {
     private GameObject[] characterList;
 
     private int index;
 
     private void Start ()
     {
         // this helps keep the array dynamic and I can add more characters later.           
         characterList = new GameObject[transform.childCount];  
 
         // Fill the array with models
         for(int i = 0; i < transform.childCount; i++)
         {
             characterList[i] = transform.GetChild(i).gameObject;
         }
 
         // we toggle off the renderer
         foreach(GameObject go in characterList)
         {
             go.SetActive(false); // now we are turing off the renderer on each character
         }
 
         // we toggle on the renderer
         if(characterList[0])
         {
             characterList[0].SetActive(true);
         }
 
     }
     
 
     public void ToggleLeft()
     {
         // Toggle off the current model
         characterList[index].SetActive(false);
 
         index--;
         if(index < 0)
         {
             // brings you back to the index
             index = characterList.Length - 1;
         }
 
         //Togggle on the new model
         characterList[index].SetActive(true);
         
     }
 
 
     public void ToggleRight() 
     {
         // Toggle off the current model
         characterList[index].SetActive(false);
 
         index++; // going towards right so add
 
         if(index == characterList.Length)
         {
             index = 0;
         }
 
         //Toggle on the new model
         characterList[index].SetActive(true);
        
     }
 
 
     public void ConfirmButton()
     {
         SceneManager.LoadScene(2);
 
     }
 }