You're putting the cart before the horse in various ways. Saying "it's a virtue to change your mind" implies you're already at the correct solution, and everyone who disagrees with you is wrong.
They may find out in a month or in a year that the opinion they hold today was wrong and change their mind again. The statement would still be true.
They may find out in a month or in a year that the opinion they hold today was wrong and change their mind again. The statement would still be true.