The SSSS Scriptorium

[NightMareMage]

Personally, I would go with the 1st of November. If only because it would be the simplest and most recognizable choice.

[Sirenade45]

Well, that depends on what exactly you consider the comic's "birthday", of course.
Page 1 was indeed the first to get publicly posted, at the date indicated, confirmed by the SSSS reference here.
Concept art publicly appeared on ARtD's gallery in 2012, and possibly even earlier someplace else (I forget what her username on DA was ...).
On the other other hand, ARtD expressedly was her "practice comic" to see whether she can do SSSS justice, so the idea of SSSS wholesale predates ARtD - which debuted uhhhihavenoidearightnow.

Edit to add: ARtD page 140 (beginning of chapter 4) is the first one to be marked with a date, 01-Jun-2012. Given her update schedule back then, I'd say that that puts page 1 into Nov/Dec 2011.

Thanks ! I think I will just take the day of the first page to keep it simple and be patient until then.
Looked on DA, her user name was just MinnaSundberg (she posted the first picture of the crew the 25 August 2014, but it's already past, so...)
Edit: Thanks too NightMareMage!

[JoB]

Looked on DA, her user name was just MinnaSundberg

I'm pretty sure that there was a different account where she had posted, among other things, all four Zarkora title pages, rather than just this one ... sorry, my names-and-faces memory is pretty dysfunctional to begin with ...