Ghost like feature

I've seen in games this feature where the player would move and after a certain condition was met a ghost would appear, and would repeat the exact same movement the player did earlier. I thought that the following code would work as i expected but it doesnt (I think it is due to the fact that I add the position and rotation of the player on the wrong loop)

Here's the code:

 using UnityEngine;
 using System.Collections.Generic;
 
 public class Player_Controller : MonoBehaviour {
 
     public Rigidbody rb;
 
     private List<Vector3> posList = new List<Vector3>();
     private List<Quaternion> rotList = new List<Quaternion>();
 
     public GameObject ghostPrefab;
 
     public bool canMove = true;
 
     private const int speed = 500;
 
     // Update is called once per frame
     void FixedUpdate () {
 
         if (!canMove) return;
 
         if (Input.GetKey("w"))
         {
             rb.AddForce(0f, 0f, speed *  Time.deltaTime);
         }
 
         if (Input.GetKey("a"))
         {
             rb.AddForce(-speed * Time.deltaTime, 0f, 0f);
         }
 
         if (Input.GetKey("s"))
         {
             rb.AddForce(0f, 0f, -speed * Time.deltaTime);
         }
 
         if (Input.GetKey("d"))
         {
             rb.AddForce(speed * Time.deltaTime, 0f, 0f);
         }
 
         posList.Add(transform.position);
         rotList.Add(transform.rotation);
 
     }
 
     //this is suposed to make a "ghost" appear and make it so he replicates the player's movement
     public void playGhost()
     {
         canMove = false;
 
         GameObject go = (GameObject)Instantiate(ghostPrefab, posList[0], rotList[0]);
 
         for (int i = 0; i < posList.Count; i++)
         {
 
             go.transform.position = posList[i];
             go.transform.rotation = rotList[i];
 
         }
     }
 }