Unfortunately, every beardie is different, so while I can say that my little girl brumated for a few weeks, it’s not unusual for a beardie to brumate for several months (I know...it sucks!).
The occasional baths you’re giving her can help a lot during this time. It’s important to ensure that a brumating beardie remains properly
hydrated since the majority of their normal water intake comes from the foods that they eat. So when they’re off of food for the winter, a water bowl should always be available. Brumation was the only time my young female beardie ever drank from a water bowl. Once in a blue moon she’d rouse from slumber, waddle to her water bowl, take a few gulps, then back to brumating. Or you can give your beardie a 10-minute soak in warm water once or twice a week to give her an opportunity to drink, which it sounds like you’re doing.
When a beardie is particularly young, I’ve heard some reptile experts recommend taking him to a vet so that the fat/nutrition pad can be weighed, a fecal test can be done, and the vet can determine if the beardie has the nutritional reserves to get through brumation. This might simply be an extra precaution/peace of mind approach in most cases, but it’s always an option if you have specific concerns (ex: she’s on the skinnier side going into brumation, ate an enormous amount of food the day she went into brumation and now it’s sitting in her gut for an extended period, etc).
I agree that there’s very little information on beardies that are less than a year old when it comes to this subject. And as you’ve found out, some beardies don’t care whether there’s a snowstorm or a palm tree outside their window—they snooze where they want when they want. But because life is always more fun with a conscious beardie, here’s hoping your girl doesn’t have too much longer to go.