Simple UI Text Question

Trying to get a score to display, but the UI is giving me error:
Object reference not set to instance of object.

I thought I had this setup properly but not sure why the error.

Script is attached to Canvas object with Text UI object as it’s child.

#pragma strict
import UnityEngine.UI;

var gameState:GameState_Lv01;//Game State Script
var pStats:PlayerStats;//Player Stats Script
var isPaused:boolean = false; //switch for pause.

var canvas:Canvas; //HUD
var timerTxt:Text; //holds the timerText to be displayed. 

var levelComplete:boolean = false;

function Start () {
	gameState = GameObject.FindGameObjectWithTag("GameState").GetComponent(GameState_Lv01); //for accessing game stats to display
	pStats = GameObject.FindGameObjectWithTag("Player").GetComponent(PlayerStats); //for accessing player attributes to display.

	timerTxt = GetComponent(Text); //setup main canvas
	timerTxt.text = (System.Math.Round((gameState.timer),0)).ToString();

function Update () {
	Debug.Log(timerTxt.text); // **??? why is this an object not the actual text?**
	timerTxt.text = "Score: " + (System.Math.Round((gameState.timer),0));

Anyone know why this isn’t giving me the timer?

You probably want GetComponentInChildren if this is attached to the canvas.

Alternatively it will work as written on the actual GameObject with the Text component attached.