Hello!
So sorry to hear your beardie is getting aggresive. I'm not quite sure when Beardies are considered "teenagers", but I'd imagine close to that age. Correct me if I'm wrong. I've heard these comparisons before, but compare her to a moody teenager "I hate you MOM!" Lol. With patience and handling this should subside. Beardies are domesticated so her wild side might be coming out. Try to brave it every once in a while and take her out of her cage.
I also have a female that gets aggresive, but she was a rescue. I don't know how old she is, but I'd imagine quite old. I can relate to how frustrating it is to only want to love and care, and be met with aggression. I've discovered my girl becomes more docile once shes out of her cage. I'm assuming that's a territorial thing. Try letting her out to roam and burn some energy, (in a closed off beardie proof room) and possibly that will help. Plus it will tell you if shes being territorial or just moody.
If thats not the case patience, and handling is what i can suggest. When theyre babies they're very skittish and the fight or flight instinct is mostly flight. She may be big enough, and accustomed enough that now she's going into fight. Also big hands coming into her house and touching her things will also make them flare up, till they get used to it. My girl does it when shes hungry mostly, if its the day before shes about to get crix she gets very moody with me.
Bonding would also be great, try putting a shirt that smells like you in the cage every once in a while, unless that causes her stress. I bonded with my other male dragon by wrapping him up like a beardie burrito right before bedtime, so he could fall asleep with me while i watched tv, and be around my smell. Then when i was ready for bed just put the whole shirt with him back in his cage. Feeding greens, crix, etc by hand is also a great way to bond. It will make your hands be related to good things, which is food mostly for beardies. They love eating.
Also I do believe she is much to young for brumation. Ive only heard that if they're a year or older will they go into brumation.
I'm no expert on beardie care, and am actually quite new to it myself, so feel free to do some research into it yourself as well, and fact check me. I wish you the best with your new beardie, and keep us updated!