I'm sort of both, like you. I can be very introverted but can also be extroverted depending on the situation. I'm just not good at being extroverted due to the anxiety and the difficulty in thinking of things to say. Sounds like we're in the same boat. I also have difficulty speaking at length about anything at all. My brain just sorta disconnects.Maybe you are an introvert.you have narrow interests . I am between extroverted and introverted. I can relate to others 50% about the things happening in my city . I guess I notice deliberately even though I am not really into them so I can relate to others. But I can't elaborate too much about the topics cuz I am not good at elaborating. So I often end up silent very quickly or just reply to the Speakers casually
I don't think I have narrow interests, I think my interests are just different than the general public. I.E. at work pretty much everyone is obsessed with sports. I personally don't give two ****s about sports. I just don't have a way to really connect to the people who share my interests due to my SA.