i have a problem in if statement

hey i am making a game in which you have to tap very fast as much as you can in 5 seconds i wanted to play a animation when the timer reaches 0 how do i do that or debug something
this is my script


using UnityEngine;
using UnityEngine.UI;
using System.Collections;
public class CountDown : MonoBehaviour
{
float timeLeft = 5.0f;
public Text text;
void Update()
{
timeLeft -= Time.deltaTime;
text.text = "" + Mathf.Round(timeLeft);

}
}