Jquery getting new value after data attribute update

I am updating link attribute values via ajax response.but When i am again clicking the button/link getting old values instead of new value.

Below is my codes;

HTML

<div class="calendar-control"><a class="evecal-month-view-control fright next-month" href="#" data-month="2" data-year="2019">Next</a><span class="text-center month-name">January 2019</span><a class="evecal-month-view-control fright prev-month" href="#" data-month="12" data-year="2018">Previous</a></div>

And Jquery code.

jQuery(document).on('click', '.evecal-month-view-control', function(e){
    e.preventDefault();
    var month = jQuery(this).data('month');
    var year = jQuery(this).data('year');
    console.log(month);
    _getMonthCalendar(month, year);
});

var _getMonthCalendar = function(m, y){
    jQuery.ajax({
        type: 'POST',
        url: eventcaldata.ajaxurl,
        data: {
            action: 'ec_ajax_month_table',
            year: y,
            month: m,
            nonce: eventcaldata.nonce,
        },
        beforeSend: function(){
            console.log('sending...');
        },
        success: function(response){
            jQuery('.next-month').attr( 'data-month', response.nextmonth.month );
            jQuery('.next-month').attr( 'data-year', response.nextmonth.year );
            jQuery('.prev-month').attr( 'data-month', response.prevmonth.month);
            jQuery('.prev-month').attr( 'data-year', response.prevmonth.year);
        }
    });
}

First on .next-month class the data-month attribute value is 2 then it is changed to 3 after response.But When i am again clicking that button i am getting 2 value when it should be 3