Unity C＃-数组索引超出范围

我在统一方面遇到麻烦，这是代码

错误信息：

IndexOutOfRangeException: Array index is out of range.
Sequence.fillSequenceArray () (at Assets/Scripts/Sequence.cs:43)
Sequence.Start () (at Assets/Scripts/Sequence.cs:23)

码：

public int[] colorSequence = new int[100];
public int level = 2;

// Use this for initialization
void Start () {
    anim = GetComponent("Animator") as Animator;
    fillSequenceArray ();
    showArray (); // just to know

}

// Update is called once per frame
void Update () {

}

public void showArray(){
    for (int i = 0; i < colorSequence.Length; i++) {
        Debug.Log ("Position " + i + ":" + colorSequence[i]);
            }
}

 public void fillSequenceArray(){
    for (int i = 0; i < level; i++) {
        int numRandom = Random.Range (0, 3);    

        if (colorSequence[i] == 0) {
            colorSequence[i] = numRandom;
        }
    }
}

我试图将最后一个更改if为if (!colorSequence[i].Equals(null))，或者 if (colorSequence[i] == null)发生相同的错误。即使删除此内容if，当我尝试填充时也会发生错误colorSequence[i] = numRandom;