How do I make a color lerp reset back to the original color after I click on a new tile?

I am making a game that utilizes a 10 x 10 grid. When the player clicks on a tile, the selected tile is supposed to slowly flash between black and green until a new tile is selected or the current tile is deselected. I achieved this effect using Color.Lerp, but the problem is when I select a new tile, the color lerp does not start over. It continues mid-cycle from the color from which it left off. For example, when I select a tile and let it fade to green then select a new tile, the new tile starts off at the same shade of green and the color lerp goes from there. I want it to start over from black. Here is my code:

 public void OnMouseDown()
     {
         SelectNewTile();
     }
 
     private void Update()
     {
         if(tileSelected)
         {
             //Makes selected tile slowly blink green
             float t = Mathf.PingPong(lerpTime, 1.0f) / 5.0f;
             selectedTile.GetComponent<Renderer>().material.color = Color.Lerp(startColor, endColor, t);
             lerpTime += Time.deltaTime;
         }
     
     }
 
     public void DeselectOldTile()
     {
         selectedTile.GetComponent<Renderer>().material.color = startColor; 
         tileSelected = false;
         lerpTime = 0.0f;
     }
 
     public void SelectNewTile()
     {
         bool canMove = false;
 
         if(!tileSelected)
         {
             selectedTile = transform;
             currentTile = selectedTile;
             tileSelected = true;
         }
         else if(selectedTile.Equals(transform))
         {
             DeselectOldTile();
             tileSelected = false;
         }
         else
         {
             DeselectOldTile();
             selectedTile = transform;
             currentTile = selectedTile;
             tileSelected = true;
         }
 
         if (selectedTile.childCount != 0)
         {
             canMove = true;
         }
 
         UpdateTileInfo(tileSelected, canMove);       
     }

I have searched everywhere for a solution and tried every possible fix that came to my mind, but nothing has worked. I even used print statements to debug it, and they printed out that when t = 0, the material color is indeed black, yet the tile was still green. I am out of options, so I will be beyond grateful for any help.