2-Dimensional Array Error [CLOSED]

Im having an issue with my code. It is giving me an error called IndexOutOfRangeException: Array index is out of range. Im not quite sure what Im doing wrong. The code is for a horror game with randomly generated levels...

Here is the code:

 using System.Collections;
 
 public class ProceduralGenerationScript : MonoBehaviour {
     public int worldX = 12;
     public int worldZ = 12;
 
     int[,] roomType;
 
     public GameObject room;
 
     // Use this for initialization
     void Start () {
         roomType = new int[worldX,worldZ];
         for(int i = 0; i <= worldX; i++)
         {
             for(int j = 0; j <= worldZ; j++)
             {
                 roomType[i, j] = 1;
                 }
 
                 //These Lines Seem To Error...
                 if(roomType[i, j] == 1)
                 {
                 Instantiate(room, new Vector3((float)i, 0, (float)j), Quaternion.identity);
                 }
 
             }
         }
     }
 }
 

The array roomType is used to index a certain room and decides what type of room it should be. Just now, it is set up to be that if roomType[i,j] is equal to 1, it will instanciate a roomplace holder(a plane). it works like this:

                 Instantiate(room, new Vector3((float)i, 0, (float)j), Quaternion.identity);

But not like this:

                 if(roomType[i, j] == 1)
                 {
                 Instantiate(room, new Vector3((float)i, 0, (float)j), Quaternion.identity);
                 }

Any help is appreciated! :-)