Hiding view filter option based on another filter selection
Run the check on page page load, not just on click:

 ... wrapped in the usual Drupal boilerplate

disableFilter($('#edit-field-agegroup-value-1'));

$('#edit-field-agegroup-value-1').click(function() {
    disableFilter($(this));
});

function disableFilter(element) {
    if( element.is(':checked')) {
        $("#edit-field-classroom-value-3").prop('disabled', true);
     } else {
        $("#edit-field-classroom-value-3").prop('disabled', false); 
     }    
}