Is my chinchilla going to be okay?

I have 3 rescue chinnies, all girls that room together. My gray girl, Aloe, is the one I'm worried about. I will say, the woman I got them from thinks that she's older than the other two (Possibly even the other girls mother). Overall, I'm not sure about their ages.

So, the issue is that I noticed how she was acting. She was doing fine yesterday, and then today when I went to check on them and feed them, she was falling over on her side and not coming up to the top platform to get any...

Is my chinchilla going to be okay?