Loading a different Scene if some buttons are checked

So I'm trying to load three specific scenes if some buttons are clicked. It is a simple loading screen that calls three other scenes which has 2 textfields(txtUser,txtPass) and 2 buttons (btnCancel, btnEnter) and 2 selecting buttons (btnStd, btnProf) which loads a fxml separately - a third fxml if both are clicked disabled

The tricky part is in this Enter button which is called after enabled or disabling two other buttons, for students and teachers. This also loads a third if both buttons are pressed: the administrator

@FXML
private void onActionBtnEnter(ActionEvent event) {
try {
if (txtUser.getText() == null || txtUser.getText().isEmpty()) {
new Message().showModal(Alert.AlertType.ERROR, "User validation",
(Stage) btnEntrar.getScene().getWindow(),"Needs username");}
else if (txtPass.getText() == null || txtPass.getText().isEmpty()) {
new Message().showModal(Alert.AlertType.ERROR, "Password validation",
(Stage) btnEntrar.getScene().getWindow(), "Needs password");}
else {
FlowController.getInstance().goMain(); //this is one of the fxlm views to load
((Stage) btnEnter.getScene().getWindow()).close(); //closes the login and loads the scene
}
}       
catch (Exception ex) {
Logger.getLogger(LandingViewController.class.getName()).log(Level.SEVERE, "Login error.", ex);
}
}

This works alright but instead of choosing specific fxml to load it only loads goMain() which contains administratorview.fxml. I also did a goMain2() and goMain3().

For students, the studentsview.fxml should load. For profesors the profesorview.fxml. Following code for buttons methods and actions

@FXML
private void onActionBtnStd(ActionEvent event) {
btnStd.setDisable(true);
txtPass.setDisable(false);
txtUser.setDisable(false);
}
@FXML
private void onActionBtnProf(ActionEvent event) {
btnProf.setDisable(true);
txtPass.setDisable(false);
txtUser.setDisable(false);
}

So far good, but loads only a single fxml because they aren't called yet. So I guess in the btnEnter action there should be some code which I tried as in (same event as above):

@FXML
private void onActionBtnEntrar(ActionEvent event) {
else if (btnStd.getValue().isDisabled()){ //added else if but I don't know how to call a boolean property in a void
FlowController.getInstance().goMain(); 
((Stage) btnEnter.getScene().getWindow()).close();}
else if (btnProf.getValue().isDisabled()){ 
FlowController.getInstance().goMain2(); 
((Stage) btnEnter.getScene().getWindow()).close();}
else if (btnProf.getValue().isDisabled() && btnStd.getValue().isDisabled()){ 
FlowController.getInstance().goMain3(); 
((Stage) btnEnter.getScene().getWindow()).close();}

Silly me, I added .getValue() in the if statement - all it was needed is to put the component.isDisabled() or .isEnabled() if it holds a boolean. However it doesn't load the adminview if both are checked disabled - it load the studentview. Investigating further...

Edit: Ok the last "else if" must be called first than the other two. It works like a charm.