Hello @Priyanka,
there is a lot of previous discussion on date formatting and age calculation in this forum. The (always recommended) search function may help you, e.g. https://community.kobotoolbox.org/t/how-to-change-the-date-format-from-yyyy-mm-dd-to-dd-mm-yyyy/25258/2.
The table screenshot indicated there seem to be more problems in your form. So, you may provide, please, a form extract with all variables/calculations around your date issue.
