Age filter not Age restriction. Is it possible?

Is there any possibilities to add Age filter in dolphin? By this filtering user under 18 can sign up but won't able to see restricted content due to their age ? Not the typical "If you are above 18- Agree" function but totally deny access to the user due to their date of birth. Also user won't change their date of birth once they entered or choose it.

You can use the Custom Privacy mod to add age filter to the Privacy settings.

For Birth date modification :
Login to Admin panel and go to Builders => Profile Fields => Edit Profile. Remove Birth date from the form.