It seems like she might be showing signs of being protective of you. I wouldn’t encourage it.

We worked on this with my girl at the dog park. Eventually she stopped being threatened by me petting other dogs, them getting in between her and I (within reason, she’s still a loyal dog I was her owner and it makes sense to want to keep close) and even me feeding them treats or throwing a ball. The key was to keep moving so she never had time to “settle down” in one spot and claim it. For a long time we absolutely could not sit on a bench and DEFINITELY not with food or she’d claim it as the castle and bark and start shit with any dog getting too close.

If that’s not it it could be a million other things. Protectiveness over her house, the chair, the room, her bone, them being rough with her, sore joints, just not wanting to be picked up (but calling her would work instead), etc.

I had my dog trained to get off the furniture whenever I needed/wanted her off. If she’d have dared growl at me or anyone for trying to remove her from the couch I would have banished her to her bed on the floor or put her outside. She preferred her bed though so it was never an issue!