Help with time.time when new scene starts.

     private float nextEggTime = 0.0f;
     private float waitTime = 4.0f;
     private float spawnRate = 1.2f;
 
     void Update () {
             Debug.Log (Time.time);
             if (waitTime < Time.time)
             {
                 SpawnEgg();
                 nextEggTime = Time.time + spawnRate;
                 //Speed up the spawnrate for the next egg
                 spawnRate *= 0.99f;
                 spawnRate = Mathf.Clamp(spawnRate, 0.85f, 99f);
                 waitTime = nextEggTime;
             }
         }
 
 

I want the SpawnEgg to start 4 second after the scene starts and this was working until i added my start scene and now this scene is at second place.( and time.time is running ) on clicking 'play button' this scene starts but because the Time.time is still running i can not get that 4 seconds behaviour again.

"is there a counter which starts for every scene ?" if not what changes i should make here ?