Oh, don't get carried away. Supergirl should be aired from March 30th to May11th (7 episodes in a row IF there is no break) then, Lois & Supeman will come back from its hiatus, on May 18th, what could mean that the remainder of the season 6 would be released this summer (August to September), knowing that the shooting of the last episodes is scheduled in August, according to David Harewood.
As the Summer audience isn't usually the one watching Supergirl and that usually, people spend little time in front of the TV at this time of year, it will be interesting to see what this will give in terms of ratings for the show.
To be honest, I am pretty divided on this return. I mean I am both delighted that Supergirl is coming back at the end of the month, what was quite unexpected (I didn't believe Azie Tesfai who has announced a releasing in April and the schedule of programs shared by CW lately, did not mention Supergirl at all in its grid) and disappointed to see that a show which already lasted 5 seasons and will release its 6th soon, will come and plug the hole while waiting for the return of Lois & Superman, the new star program and, will see a good part of its last season aired during a time which does not correspond to its usual programming, what does not usually bode well. It's a little degrading, IMHO. Yes, the quality gradually reduced like ratings, season after season, even s4b was pretty good but, making such a drastic programming change, it's a little brutal!