When I pause during the countdown the game does not freeze PLS SOMEONE HELP.

When I press the pause button during the countdown to start the game, the game goes to the pause menu but does not freeze the game.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 //This is the countdown script
 public class DelayedStartScript : MonoBehaviour
 {
 
     public GameObject countDown;
 
     // Start is called before the first frame update
     void Start()
     {
         StartCoroutine("StartDelay");
     }
 
     // Update is called once per frame
     void Update()
     {
         
     }
 
     IEnumerator StartDelay ()
     {
         Time.timeScale = 0;
         float pauseTime = Time.realtimeSinceStartup + 4f;
         while (Time.realtimeSinceStartup < pauseTime)
             yield return 0;
         countDown.gameObject.SetActive(false);
         Time.timeScale = 1;
     }
 
 }