I think I've had mental shifts my entire life...
Sometimes I suddenly just feel like I'm suddenly in first person looking through my own eyes and in my own self. I'm not saying I don't experience life in first person normally, or that I'm ever not in first person. I'm always in first person, that's normal, but sometimes it just feels like I'm in super first person or something. And then it just fades away unnoticeably.
It's kinda like when you are trying to meditate and you focus on your breathing to not have any thoughts, or try to silence your internal voice, but without focusing on anything or trying consciously to silence your internal voice. Like, suddenly my internal voice is silent unless I consciously choose to use it.
Like instead of it being hard to silence your internal voice, and it's constantly talking, it becomes effortless. If you don't purposely decide to think or comment about something in your mind your mind is just silent. But I still just know instinctively what I want, what to do, ect.
Also sometimes it's hard to speak, or the words come out jumbled/wrong, but if I focus I can speak, it just takes a little bit more effort. I've had this happen to me my whole life, I've thought it was something everyone experienced until I mentioned it to my brother and he had no idea what I was talking about.