Input and checkbox validation using AngularJS

I have a page with a check box representing "All dates" and two input fields which represent the start date and end dates. When the page first loads the check box is unchecked. The requirement is if the check box is unchecked and there is nothing in the start and end date fields a message must display to the user.

This is what I have for the check box and input fields and the error message:

<input name="dateSelectAll" type="checkbox" ng-model="$parent.vm.selectAllDates" ng-required="$parent.vm.selectedReport.Parameters.StartDate == null || $parent.vm.selectedReport.Parameters.EndDate == null" />All Available Dates

<input name="beginningDate" type="text" class="form-control form-field" datepicker-popup="dd-MMM-yyyy"
           ng-disabled="$parent.vm.selectAllDates"
           ng-model="$parent.vm.selectedReport.Parameters.StartDate"
           is-open="beginningDateOpened"
           ng-required="$parent.vm.selectAllDates == false"
           close-text="Close" />
<input name="endDate" type="text" class="form-control form-field" datepicker-popup="dd-MMM-yyyy"
           ng-disabled="$parent.vm.selectAllDates"
           ng-model="$parent.vm.selectedReport.Parameters.EndDate"
           is-open="endDateOpened"
           ng-required="$parent.vm.selectAllDates == false"
           close-text="Close" />

Please select

This is what I have in the controller at the beginning:

vm.selectAllDates = false;

This is what I have in the submit function:

if ($scope.reportForm.$valid) {
                //do stuff
            }
            else
            {
                $scope.reportForm.submitted = true;
            }

If the form is "valid" when I hit the submit button a modal window will display.

What's happening is the page loads and if I don't enter in dates or check the check box and I hit submit, the message appears and I can't submit which is fine.

When I check off the check box the message stays but I can submit.

When I uncheck the check box and enter dates the message stays but I can submit.

How do I hide the message once any of the conditions have been met? Sorry! I'm still a newbie at Angular.