It's a little late now (since it's long past the 19th in Japan) but September 19th is Sakurachi Riko's of Aqours' birthday!
Also, on September 21st, we have another birthday of Aqours, Kurosawa Ruby! (no birthday image as that isn't for another 19 hours in Japan)
~~
Love Live anime spoilers a bit ahead
On a side note, I wanted to talk about Riko and something I was informed of earlier, which got me to thinking a bit. Riko is shown in the preview to their PV to have a 1st year's ribbon from Otonokizaka, the school u's is from.
And that's what got me to thinking. The leader of Aqours, Chika, wanted to form an idol group after witnessing some performances from u's on the internet/TV (something, I'm not sure) around the end of Chika's 1st year, and she's becoming a 2nd year, just like Riko. With that in mind, it's safe to assume if Chika is just learning of u's, u's is currently a large topic, AKA they're still a full group and getting coverage, so Aqour's group is formed the following school year after u's breaks up. Knowing that Riko spent her first year at Otonokizaka, and is currently a 2nd year at the school Aqours comes from, you can conclude that Riko was not only at Otonokizaka the year u's was formed, but that since there's only a single First Year's class (as stated by Honoka in the first couple episodes of the anime), Riko was in the same class as Rin, Hanayo, and Maki.
My mind was blown when I came to that realization.