How do I make scenes switch properly c#

I am having problem . I trying to make the scene switch base on time . I can't get it to work . What trying to do is see if the timer check for the score when it reaches zero . The player has to score a require amount of points . I will you an example . If I have the score set 100 points ... the timer should be checking to see if I had score the points when the timer reaches zero . If the player has score the require point then the next plays . I got the scene to switch but the problem I am having it's going back to the same level . The script is focus is on that . Here is my code :

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 using UnityEngine.SceneManagement;
 
 public class TestScript : MonoBehaviour
 {
     public MyClockScript myClock;
     public ScoreManagerScript scoremanager;
     
     public int scoreToReach = 99;     // change this value to what you want
     
     public string nextScene = "FY"; // change this value to what you want
 
     void Update () 
     {
           if (myClock.m_leftTime <= 0)
               {
               if ((ScoreManagerScript.score >= scoreToReach) && (nextScene != "FY"))
                      {
                      SceneManager.LoadScene(nextScene);
                      }
               else
                     {
                      SceneManager.LoadScene(SceneManager.GetActiveScene().name);
 
                     }
                }
     }
 }