How to delay Update() until Start() has finished?

public IEnumerator Start()
{
yield return StartCoroutine( imagine, say, an opening animation );
}

public void Update()
	{
	do not start moving, until that opening animation is done
	ongoing movement etc.
	}

I’ve always just done this with a simple flag:

public void Update()
	{
	if ( still doing that opening animation boolean ) return;
	ongoing movement etc.
	}

Is there perhaps some inherent way to know if Start() has not yet completed? Or another amazing solution? Cheers!

You can disable the script in Start().

Do this using enabled = false, same as anywhere else.