she is around other cats who are not her mom and are all bigger than her. I'm sure that's what prompted her to perfect the puffed up, tough girl look.
Ember, on the other hand, is an only cat. She came from a multi cat home that also had a dog. By the time I got her, her older half brother had attacked her and the dog had protected her. Her human had roughed her up. My home was like a safe haven to her. She did do zoomies so fast that she would have left Superman in the dust.
When I'd only had her a week, she growled once at a visiting friend of mine who got too close too soon. But no crab walking until she was 5 months old and a "stranger" walked into the apartment after knocking, without me opening the door for him. The stranger was a maintenance guy who works for my landlord and I was expecting him. But to Ember, he was a dangerous intruder who barged in on us. She instantly puffed up and crab walked around him while he cracked up laughing at her. I think that she was put off by being laughed at. She never accepted that guy afterward.