Animation Scripting Help #C

I keep getting this error:
NullReferenceException: Object reference not set to an instance of an object
EnemyAnimation.Start () (at Assets/The Game/Scripts/EnemyAnimation.cs:24)

I am really new to this and I would really appreciate some help!

using UnityEngine;
using System.Collections;

public class EnemyAnimation : MonoBehaviour
{
		Animation _animation;
		// Use this for initialization
		void Start ()
		{
				_animation = GetComponentInChildren<Animation> ();
				string animationToPlay = "";
				switch (Random.Range (0, 3)) {
				default:
				case 0:
						animationToPlay = "Move1";
						break;
				case 1:
						animationToPlay = "Move2";
						break;
				case 2:
						animationToPlay = "Move3";
						break;
				}
		_animation [animationToPlay].wrapMode = WrapMode.Loop;
		_animation.Play (animationToPlay);
		_animation[animationToPlay].normalizedTime = Random.value;
		}
	
		// Update is called once per frame
		void Update ()
		{

		}
}

Ive added the script to the enemy, but it is still not working