I had a database that had a perfectly working NOW() function, displaying the right date.
And after accidentally deleted it, I created a similar database, but when I inserted NOW
You have quotes around the NOW() function. Change it to:
INSERT INTO `blog_details` (`title`, `blog_content`, `blog_date`, `cat_name`)
VALUES('Breaking Bad TV Series', 'Best series evar', NOW(), 'Uncategorized');