Congrats! I know right? I got a weird e-mail yesterday saying that I should log-in to my extranet account, and I just assumed it was related to my re-submitted application. Thought it was weird to get word so soon for this cycle. Today before lunch got another e-mail and thought it was a sketchy e-mail... but since the e-mailed yesterday, I decided to jump in and click the link. Good thing I did, haha!
I think they will retroactively pay you, it has happened to me before for another award, so I don't imagine it would be much different. I think if you wanted to graduate May 2023, you should choose May 2020 for a PGSD3 for example, so that the fiscal periods align... but I'd double-check with your department regarding this.