A failed cooldown

Hello to all, i’ve got a problem, i make a cooldown, but, whatever i make, it’s always = 0

The script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SlowMotion : MonoBehaviour {

public float currentBulletTimer = 0f;
public float bulletTimeAllowed = 1f;
public float bulletTimeCooldown = 15f;

void Start () {
	
}

// Update is called once per frame
void Update () {
    {
        if (Input.GetKeyDown(KeyCode.Mouse1) && (bulletTimeCooldown >= 0))
        {
            
            if (Time.timeScale == 1.0)
            {
                Time.timeScale = 0.3f / bulletTimeAllowed;
            }
            else
                Time.timeScale = 1.0f;
        }

        if (Time.timeScale <= 0.9)
        {
            bulletTimeCooldown = 15;
            currentBulletTimer += Time.deltaTime * bulletTimeAllowed;
        }

        if (currentBulletTimer >= 1)
        {
            currentBulletTimer = 0;
            Time.timeScale = 1.0f;
        }

        if (bulletTimeCooldown < 0) ;
        {
            bulletTimeCooldown = 0;
        }

        if (bulletTimeCooldown > 0)
        {
            bulletTimeCooldown -= Time.deltaTime * bulletTimeAllowed;
        }
            
    }
}

}

I need help !