When exactly is DJ's birthday?

I recently read online that her date of birth is officially listed as being February 9, 1977. So what's the big deal? Well, in Season 3, her 13th birthday was celebrated. If I'm not mistaken though, that particular season began at the end of summer. Her birthday episode is therefore, apparently set in between the Thanksgiving and Christmas episodes.

Also keep in mind that in Season 2 of Fuller House, Danny turned 60. And in Season 5, DJ herself, turned 40. So this would've made their ages different by 23 years rather than the 19 year gap in the original series. Danny's birthday is officially listed as being on December 11, 1957.