Hi @nadheemabdulla,
Here is a little demo which is consist of just one extra field(phone number).
It works and has possibility download data as CSV format, from the Django admin side. Actually I tried to make “Gender” and " Date of birth" as Required fields, but that was not easy for me, bacause overridding fileds which already exist, effects the other fields. But you can try that on your test server. And this example from Appsembler
may can help you for overidding existing files.
Thanks and god luck !