iOS Email Validation with modal alert in Swift

I am a beginner with Swift, iOS, and Xcode. I am working on a multi-scene grading app done through a storyboard in Xcode 7 for a class assignment. One of my scenes is a register page and I need to validate the email.

Here's what I have, the following code is on the view controller that pertains to the register page and outlets exist for each field. I am trying to use shouldperformseguewithidentifier to either allow or prevent the segue on the register button from taking place - not working. However, I know my email validation method is working because I can manually test it in a playground and see it. When I run the app, the segue goes right to the menu regardless of the validity of the email text. I'm not too sure if the actual value is coming from the textfield. I'd like to use a print statement to check but I don't know where the output is shown while testing in the simulator.

So the desired outcome of the code below which is generating no errors or warnings is to stop the segue if the email is invalid and then to present a modal alert to the user using UIAlertController. Can someone please tell me what I'm doing wrong?

class StudentRegisterKappa: UIViewController {

@IBOutlet weak var firstName: UITextField!
@IBOutlet weak var lastName: UITextField!
@IBOutlet weak var email: UITextField!
@IBOutlet weak var phoneNumber: UITextField!
@IBOutlet weak var userName: UITextField!
@IBOutlet weak var password: UITextField!

override func shouldPerformSegueWithIdentifier(identifier: String, sender: AnyObject?) -> Bool {

    if identifier == "kappaToMenu" {

        if validateEmail(email.text!) {

            return true

        } else {

            let alertView = UIAlertController(title: "Invalid Email", message: "Try Again", preferredStyle: .Alert)
            alertView.addAction(UIAlertAction(title: "Ok", style: .Default, handler: nil))
            presentViewController(alertView, animated:true, completion:nil)

            return false
        }

    }
    //default
    return true
}

func validateEmail(candidate: String) -> Bool {
    let emailRegex = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,6}"
    return NSPredicate(format: "SELF MATCHES %@", emailRegex).evaluateWithObject(candidate)
}

}