Need help with delaying a timer (javascript)

Ok I currently have my scenes running like this.

Main Menu
|
Player Select
|
Level 1

In the Level 1, I have a script (Level1InfoScript) that has a timer that countsdown and when it hits zero it will end the level (haven't written that part yet). My problem is that the timer starts counting down right when the game is launched on the main menu, instead of waiting until Level1 is loaded to countdown. Making it look like this.

Main Menu(this is when the timer starts)
|
Player Select
|
Level1 (this is where the timer is suppose to start)

I'm very new to programming and stuff, so any help or advice would be great. I looked on here before asking, and found a somewhat similar question, but the advice given in that wasn't working, so that why I am now here myself.

Here is the code. I got most of the code from a Unity Beginners Guide book and building from there. I have omitted stuff that doesn't pertain to the timer itself.

 var isPaused : boolean = false;
 var startingTime : float; // This is in seconds
 var timeRemain : float; // Also in seconds
 
 function Start()
 {
     startingTime = 20.0;
 }
 
 function Update ()
 {    
     if(!isPaused)
     {
         //To make sure the time is not paused
         StartCountdown();
     }
 }
 
 function StartCountdown()
 {
     timeRemain = startingTime - Time.time;
     if(timeRemain < 0)
     {
         timeRemain = 0;
         isPaused = true;
         TimeUp();
     }
     ShowTime();
 }
 
 function ClockPause()
 {
     isPaused = true;
 }
 
 function ClockUnpause()
 {
     isPaused = false;
 }
 
 function ShowTime()
 {
     var minutes : int;
     var seconds : int;
     var timeStr : String;
     
     minutes = timeRemain / 60;
     seconds = timeRemain % 60;
     timeStr = minutes.ToString() + ":";
     timeStr += seconds.ToString("D2");
     guiText.text = timeStr; //shows the time in the GUI
 }
 
 function TimeUp()
 {
 
 }