NullReferenceException Error is driving me crazy, it asks me for a reference when I think I put one

Hello! I'm trying to start up a play button by setting the active of an UI element, sadly when I try to run the game it tells me that the object reference is not set, when I think I set it up correctly.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class PlayerControl : MonoBehaviour {
 
     public GameObject GameManagerGO;
 
     public GameObject PlayerBulletGO;
     public GameObject BulletPosition;
     public GameObject ExplosionGO;
     public Text LivesUI;
     const int MaxLives = 10;
     int lives;
     public float speed;
     
     public void Init()
     {
         lives = 5;
         LivesUI.text = lives.ToString();
     }

Thank you for any help ><, and sorry for formatting or any errors, its my first time asking here ^^