Hi Snehal,

1. Create one Filed in Task table.

2. Create Schedule job Daily it will run . This scheduled job will calculate the Active tickets age how many days back ticket is created.

Scheduled job:

var gr = new GlideRecord("task");

gr.addEncodedQuery('sys_class_name=incident^ORsys_class_name=problem^ORsys_class_name=sc_req_item');

gr.addActiveQuery();

gr.query();

while (gr.next())

      {

      var currentTime = gs.nowDateTime(); // Get the current date time in users timezone

      var createdOn = gr.sys_created_on.getDisplayValue(); // Task created time in GMT(system default time zone)

      var datedif = gs.dateDiff(createdOn, currentTime,true); // calculate in seconds

      if(datedif<86400)

              {

              gr.u_age = 0;

      }

      else

              {

              gr.u_age = (datedif/86400);

      }

      gr.autoSysFields(false);

      gr.update();

}

Please Hit Correct if this helpful