Not expecting void Start

Hi, I'm trying to make a very basic melee attack, but when I tried adding a cooldown to the attack, I got the error "...(10.12):error CS1519: Unexpected symbol 'void' in class, struct, or interface member declaration" My problem is that the error is refereeing to the "void Start" in the initialization, which has to be there, what did I do wrong? Here's the code, thanks a bunch.

 using UnityEngine;
 using System.Collections;
 
 public class PlayerAttack : MonoBehaviour {
     public GameObject target;
     public float attackTimer;
     public float coolDown
 
     // Use this for initialization
     void Start () {
         attackTimer = 0;
         coolDown = 2.0f;
     }
     
     // Update is called once per frame
     void Update () {
         if(attackTimer > 0)
             attackTimer -= Time.fixedDeltaTime;
         
         if(attackTimer < 0)
             attackTimer = 0;
         
         if(Input.GetKeyUp(KeyCode.F)) {
             if(attackTimer ==0){
                 Attack();
                 attackTimer = coolDown;
             }
         }
         
     }
     
     private void Attack() {
         float distance = Vector3.Distance(target.transform.position, transform.position);
         
         Vector3 dir = (target.transform.position - transform.position).normalized;
             
         float direction = Vector3.Dot(dir, transform.forward);
         
         Debug.Log(direction);
         
         if(distance < 2.5f) {
             if(direction > 0) {
             EnemyHealth eh = (EnemyHealth)target.GetComponent("EnemyHealth");
             eh.AddjustCurrentHealth(-10);
             }
         }
     }
 }