Why is my Array going out of bounds??

 using UnityEngine;
 using System.Collections;
 
 public class XY_MoveScript1 : MonoBehaviour
 {
   
     //Movement Parameters.
     public Transform[] points;
 
     public bool startAutomaticly;
     public bool startFromTrigger;
     public bool enableMultiPoints;
 
     public GameObject triggerObject;
     public Vector3 offset;
 
 
     public float speed;
     public float delayStartBy = 0;
     private bool go;
     private Transform destination;
    
     private bool yes;
     public bool switchIt = false;
     int currentPoint = 0;
 
     void Awake() { transform.position = points[0].position; }
    
     void Start()
     {
         //---------------Through Errors if Needed----------------
         if (!startFromTrigger && !startAutomaticly) { Debug.LogError("You have not specified to StartAutomaticly or StartFromTrigger!" + this.gameObject); return; }
         if (startAutomaticly && startFromTrigger) { Debug.LogError("You have StartFromTrigger And Start automaticly checked on " + this.gameObject + "!"); return; }
         if (startFromTrigger && !triggerObject) { Debug.LogError("You have Start from trigger checked, but you forgot to apply the TriggerGO1 prefab!" + this.gameObject); return; }
         //-------------------------------------------------------
 
         if (points.Length > 2) { enableMultiPoints = true; }
         destination = points[currentPoint];
         if (startAutomaticly)
         {
             StartCoroutine(WaitTime());
         }
         else if (startFromTrigger)
         {
             go= false;
             GameObject trigger = Instantiate(triggerObject, transform.position + offset, transform.rotation) as GameObject;
         }
     }
 
     void Update()
     {
         destination = points[currentPoint];
         
         //So currentPoints isn't greater than points length. Or less than 0.
         if (currentPoint >= points.Length) { currentPoint = points.Length; }
         if(currentPoint <= 0) {currentPoint = 0;}
 
         if (go && enableMultiPoints)
         {
             float step = speed * Time.deltaTime;
             transform.position = Vector3.MoveTowards(transform.position, destination.position, step);
 
 
             if (currentPoint == points.Length) { switchIt = true; }
             if (transform.position == destination.position && !switchIt)
             {
                 currentPoint++;
             }
             else if (transform.position == destination.position && switchIt)
             {
                 currentPoint--;
             }
 
             
         }
         else if (go && !enableMultiPoints)
         {
             float step = speed * Time.deltaTime;
             transform.position = Vector3.MoveTowards(transform.position, destination.position, step);
 
             if (transform.position == points[1].position)
             {
                 destination = points[0];
             }
             else if (transform.position == points[0].position)
             {
                 destination = points[1];
             }
         }
 
     }
     private IEnumerator WaitTime()
     {
         //Wait this long.
         yield return new WaitForSeconds(delayStartBy);
         go = true;
     }
 
 }