Moving a character to a waypoint

I have a character named damsel that spawns at a random point and then is supposed to move to a way point at the centre of the screen. The problem is the damsel wont move after spawning and i get error:

NullReferenceException: Object reference not set to an instance of an object

Iv had this error plenty of time before but this time I’m just not sure what to do about it, here is the code:

public class Damsell : MonoBehaviour
public float moveSpeed = 1f;
public float health = 1f;
private Transform target;
public Transform centreWaypoint;

void Start()
    centreWaypoint = CentreWaypoint.centrepoint[0];

void Update ()
    Vector3 dir = centreWaypoint.position - transform.position; //this is the line with the error
    transform.Translate(dir.normalized * moveSpeed * Time.deltaTime, Space.World);

Ill keep working on it, I’m sure the answer is staring at me but i am quite new to this.

Then check your inspector to see if you’ve properly assigned stuffs.