DC Universe's Stargirl will be coming sometime in 2020, according to an announcement from DC at this past weekend's WonderCon in Los Angeles.
That is a new date, contrasting with a schedule DC released in October 2018 that listed the show for a August/September 2019 debut.
Here is that schedule, released during October 2018's New York Comic Con:
As the fine print read, however.... "subject to change."
Swamp Thing has since been announced to debut May 31, with Harley Quinn coming in the "fall". A second season of Titans has also been added to the fall 2019 release slate.