Frozen 2

Hi, all! Sorry it has been so long. It's been crazy! Anyway, today I have something very exciting to talk about!
It was just announced that Disney is officially making a sequel to their hit movie "Frozen." I love Frozen as much as anyone, but I was wondering what it could be about. I mean, the story was pretty open and shut. There's not much more, if anything, else to tell.
Then, I found this song on YouTube:
It's a song sung by Idina, the voice of Elsa, about the Snow Queen's powers and all. There has been uncertainty about whether it's going to be in Frozen Fever, the short in front of the new live-action Cinderella, or Frozen 2. In any case, it seems to be a little bit odd. It still sounds like Elsa is wary of her powers, even though she seemed to fully accept them and gain control of them by the end of the original film. So what's going on?
My theory is that Frozen 2 will be a prequel. It might delve into more detail of how Anna and Elsa grew up, and how each of the girls felt in their isolation. This was glazed over in the "Do You Wanna Build a Snowman?" montage, and they could do something with that, possibly enough for an entire film. That would be really intriguing!
Or, it just occurred to me, it's possible that Frozen 2 takes place after the events of the original, and this is maybe a flashback song. Oh, well. Only time will tell!