Personally, my answer to “why am I me” is similar to the anthropic principle. If you were anyone else, you would be asking the exact same question, and if you were nobody, you would not be able to ask the question. By asking the question, you must necessarily be somebody, and the question would be the same no matter which somebody.
Your answer works when you are observing the person(s) from outside, referring to a third person (A and B are both conscious, so it doesn't matter which one is which). However, it doesn't answer when one of the subjects is "I", because I and everyone else is clearly different (hence the title of Benj Hellie's paper I linked above: Against Egalitarianism):
> The ‘god’s eye’ point of view taken in setting up the egalitarian metaphysics does not correspond to my ‘embedded’ point of view ‘from here’, staring out at a certain computer screen. The god’s eye mode of presentation of the Hellie-subject and the embedded mode of presentation of myself are different: as different as the manifest and scientific modes of presentation of water—indeed, perhaps even more so: that is the core of the Humean worry. So it is not a priori that any of those subjects is exactly the same thing as me. And if not, if I am told that it is this one that is me, I want to know why that is.
No, only you will refer to yourself as "I". The other one will call themselves "I" but it's not the same "I" as you. For all we know you are not even sure that the other one is really a conscious being or a robot powered by an AI that could pass the Turing test [1].
> I still don't see what is difficult about this.
You have been dismissing two of the most profound questions of philosophy, and unfortunately I am not able to explain the questions (let alone attempt to answer them) any better. There is some serious philosophical and neurological research [2] related to this subject. Maybe you should spend some time yourself researching the literature.
