RORY: Max is staying over.
RORY: First time. And to kind of celebrate, he and my mom wanted to go on a double date.
DEAN: But tomorrow’s our anniversary.
RORY: No it’s not, it’s on the twenty-fourth.
DEAN: No, that was our old anniversary. We broke up, and got back together on the sixth. So using the twenty-fourth wouldn’t be an accurate account of how long we’ve been together.
This is the point where we learn Rory’s birth date, as Rory and Dean date their relationship from the day after her birthday, when Dean gave her a bracelet in Rory’s Birthday Parties. According to this scene, that happened on October 24, so Rory’s birthday is October 23.
(That means their anniversary dinner should have been on the 24th day of a month too, January 24, but although it actually happened in March, it doesn’t fit the timeline of events to be March 24.)
In real life, October 23 2000 was a Monday, not a Friday as in Gilmore Girls (so October 24 2000 was a Tuesday, not a Saturday).
We also learn that Rory and Dean were reunited on Friday May 6 2001 – we know it was a Friday, because Rory was at school, and the next day was a weekend. In real life, May 6 2001 was a Sunday. May 6 doesn’t fit the timeline we are given in the show, where Rory and Dean are shown getting back together around mid-May.
As Dean is preparing to celebrate their monthly anniversary on August 6, the next day, it must be August 5 in this scene. It is the same day as the previous scene Rory had with Lorelai (she is wearing the same clothes) which seemed to be a Friday. As Max is coming for the weekend, Friday seems to be correct. In real life, August 5 2001 was a Sunday.
Rory and Dean’s conversation tells us that Max and Lorelai’s wedding is planned for Saturday 20 August 2001 – two weeks and one day away.
(Rory and Dean decide they will celebrate their “anniversary” twice a month, on both the 6th and the 24th.)