Beginner having trouble with NullReferenceException

Hey all,

I am almost entirely new to using unity, so I started with watching the Cooking with Unity series which was going great up until I reached the second episode and I got this NullExceptionReference for the code that is supposed to move the Enemies across the x axis. It is also supposed to keep them from going off the screen.

The error keeps saying

NullReferenceException UnityEngine.Camera.WorldToScreenPoint (Vector3 position) (at C:/BuildAgent/work/7535de4ca26c26ac/Runtime/ExportGenerated/Editor/UnityEngineCamera.cs:327) EnemyAI.Update () (at Assets/Cooking With Unity/EnemyAI.cs:25)

Here's what was told to be typed. I've watched the first and second one at least 3 times and compared his code to mine too many times. And yet, his works fine, while mine doesn't.

 using UnityEngine;
 using System.Collections;
 
 public class EnemyAI : MonoBehaviour {
     
     public float rightEdge;
     public float leftEdge;
     public float speed;
     
     private int direction = 1;
 
     // Use this for initialization
     void Start () {
     
     }
     
     // Update is called once per frame
     void Update () 
     {
         Vector3 newPosition = transform.position;
         newPosition.x += speed * direction * Time.deltaTime;
         transform.position = newPosition;
         
         
         if(Camera.current.WorldToScreenPoint(transform.position).x > Screen.width)
         {
             direction = -1;
         }
         else if(transform.position.x < leftEdge)
         {
             direction = 1;
         }
     }
 }