No, you haven't done that.
I may have memory of always existing. However, that would be irrelevant. If I told you about it, and you accepted my evidence, and presented it back to me as evidence, it could only represent evidence of my immortality. I require evidence, from you, of my mortality.
I may have no memory of always existing. However, that would be irrelevant also, given that human beings, apparently, (and, for all anybody knows, immortals) have no knowledge of the rules governing immortality. Perhaps immortals don't have such memory. Plenty of human beings suffering amnesia have no memory of having lived in previous periods. That doesn't constitute evidence that they didn't live in those periods.
I would like to propose this as a thread for people to write in their predictions for the next year and the next decade, when practical with probabilities attached. I'll probably make some in the comments.