I think if she just said that she was tired from moving and unpacking and then left it at that instead of rambling on about how its okay to be an 'introvert,' and not socialise to justify her behaviour it would be genuine especially as it came off as rather scripted as it was something from an Instagram post she read or from her therapist.Maybe if she just said "I am tired of travelling and unpacking. It was a long day after doing practically nothing at home for a longer time period, so I skip tonight" would have come off as more genuine than just saying that she skips getting know new people because she is introverted. Back in the day, I didn't want to go to these events because in case of my university, it always meant heavy drinking and hooking up, and I personally preferred socializing in between classes with those in my course, while enjoying the evenings with my roommates (three of us shared one room). I consider myself a more introverted person but communication and meeting people in cases like this is important. I hope she will make an effort to know at least those she'll studying with and make some friends - I really hope she gets better mentally.
She is really clinging on to the introvert identity these days. I don't know if she does this to justify isolating herself at home and at university, and basically this whole gap year she has had and all of her behavior. I'm expecting a lot more 'introvert ' Oxford videos.