Reset vector 2 offsets

Hi, a friend of mine showed me a script for animating sprites but when I used it i though there would be a command to make it so the game would reset the sprite animation. I've tried a lot and have not found any sort of answer. I know what it does though, it continues to move the offset.x even when it's set to zero(so if i go to 0, it keeps playing the animation discreetly so instead of it going from 0 to 0.125, it goes to anything that was going at the time like 0.5 or something)

     function SetSpriteAnimation(colCount : int,rowCount : int,rowNumber : int,colNumber : int,totalCells : int,fps : int){
 
     // Calculate index
     var index : int = Time.time * fps;
     // Repeat when exhausting all cells
     index = index % totalCells;
 
     // Size of every cell
     var size = Vector2 (1.0 / colCount, 1.0 / rowCount);
    
     // split into horizontal and vertical index
     var uIndex = index % colCount;
     var vIndex = index / colCount;
     print("Nope");
     // build offset
     // v coordinate is the bottom of the image in opengl so we need to invert.
        if (Input.GetButtonDown("Fire1")){
  offset.x = 0;
  reset = true;
  uIndex = 0;
  index = 0;
  colNumber = 0;
  size.x = 0;
  timer++;
  }
  if (timer == 2){
   reset = false;
  timer = 0;
  }
  if (reset == false){
  index = index % totalCells;
   uIndex = index % colCount;
     offset = Vector2 ((uIndex+colNumber) * size.x, (1.0 - size.y) - (vIndex+rowNumber) * size.y);
 
 }
 
     renderer.material.SetTextureOffset ("_MainTex", offset);
     renderer.material.SetTextureScale  ("_MainTex", size); 
     }

this is what I have for a script so I'm wondering what to do, so if you could help me that would be very nice.