Open mouth

Does she make any noises when she opens her mouth? Mine stretches out his jaw/beard in the morning while he basks. As far as I know that's perfectly normal. Listen closely to her breathing though.

She could also be a bit overhydrated if she's got runny stool. How old is she and what do you feed her? What are temps/humidity levels like?

You'd be listening for any whistling or clicking sounds if she has a respiratory infection. It's not very loud though, so you have to listen pretty closely for it. For the cool side of your tank you should probably err more towards the upper 20s rather than mid 20s during the day. How hot does her actual basking spot get (like surface temp, not ambient temp)? What do you use to take your temps?

It does kind of sound like she might be trying to go into brumation, but I think that's kind of unusual for her age. Some more experienced beardie owners would probably be able to guide you on that topic better than I could though. Mine is the same age and hasn't even remotely tried to go into brumation this season.

Like ncc74656 mine does mouth breathe sometimes when he's starting to shed, because the old skin plugs his nose. So she could very well be getting ready to shed as well.