I basically need to use insertBefore and appendChild with a Server Side rendered HTML page jQuery AJAX result. I get the error: "Failed to execute 'inserBefore' on 'Node': parameter 1 is not of type 'Node'."

var parent_elem = $('#parent_elem');
$.ajax({
    type:'POST',
    url:'example.com/my_ajax_call',
    data: {"my_data":my_data},
    success:function(data){
        parent_elem.prepend(data); //THIS IS THE JQUERY SOLUTION BUT I NEED PURE JS WHILE USING JQUERY AJAX REQUEST
    },
    fail:function(data){
        console.log(data);
        console.log('failed to load page');
    }
});

what I am trying to do is this:

var parent_elem = document.getElementById('parent_elem');
$.ajax({
    type:'POST',
    url:'example.com/my_ajax_call',
    data: {"my_data":my_data},
    success:function(data){
        parent_elem.inserBefore(data, parent_elem.firstChild); //THIS IS WHAT I NEED BUT IT THROWS ERROR "Failed to execute 'inserBefore' on 'Node': parameter 1 is not of type 'Node'."
    },
    fail:function(data){
        console.log(data);
        console.log('failed to load page');
    }
});