Cannot use instance member 'Numero' within property initializer; property initializers run before 'self' is available

Question

So I'm trying to make a simple Numeral System Converter, so I need to get a string variable from a Text Field. Or so was my solution thus far.

Thing is, when I try to do so it gives me that error.

The involved code right now is:

    @IBOutlet weak var Numero: UITextField!

    override func viewDidLoad() {
    super.viewDidLoad()

    Numero.delegate = self
    // Do any additional setup after loading the view.
}

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    Numero.resignFirstResponder()
}


 var num: String = Numero.text
 // Cannot use instance member 'Numero' within property initializer; property initializers run before 'self' is available //

I don't quite understand what's wrong. After watching a couple tutorials, they all use the same format with no errors.

What could be my mistake?