How to scroll table view to cell when user clicked on text view in this table view cell

Question

I found a solution of this here:

How to scroll UITextView above Keyboard in a UITableView in swift

But I want it to be right above the keyboard +10-20px.

I tried this to add an observer in viewDidLoad() to find out keyboard height:

var keyboardSize: CGRect?  

override func viewDidLoad() {
    super.viewDidLoad()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
}

override func viewWillDisappear(animated: Bool) {
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        keyboardSize = (userInfo[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue()
        println(keyboardSize)
    }
}

Then in textViewShouldBeginEditing I get a point from textView tableViewCell to tableView and trying to subtract keyboard.height from contentOffset.y value.

func textViewShouldBeginEditing(textView: UITextView) -> Bool {
    var pointInTable:CGPoint = textView.superview!.convertPoint(textView.superview!.frame.origin, toView: tableView)
    var contentOffset:CGPoint = tableView.contentOffset
    contentOffset.y = pointInTable.y
    if keyboardSize != nil {
        contentOffset.y -= keyboardSize!.height
    }
    tableView.contentOffset = contentOffset
    return true
}

When i run the application and click in textView for the first time it doesnt work but for the second time it works like this.

Everything is fine but I want it to work for the first time and one more thing: if i click on textView in cell at the bottom of tableView and then click in textView in the first cell it will work like this. But i want it to be at the top of the screen if keyboard doesn't hide it.