Unless you are immortal, then the first sentence of your argument will be right, and if you were immortal, then for you there were be no point of life, but you aren’t, you will die someday, and for everything that have an end there is a start.
True the first humans didn’t have as a point of life “pointing and correcting mistakes”, you are not one of them, neither am I, so this particular point fits on both of us, PS you are rejecting people who believe in reincarnation.
It’s also true that the point or meaning of life is highly depending on the definition of life; does life extend to the after-death? The two quotes I gave you can be thought of beyond the definition of life, you actually missed the point on both of them; am not even sure you did some serious thinking about what I said, am not going to go about the rest of your argument because they don’t fit in the context (philosophically), we weren’t always the dominant species at earth, also I’ll remind you that some previous dominant species caused the extinction of other species(example: dinosaurs), nature rages did the same(ace age)…, at least we are aware about it, hopefully to correct the damages we are doing…
Finally answering your last paragraph, the answer is in this two quote, it’s not about the beginning or the end, the point of life is what’s between its beginning and its end, whether life start good or bad, life itself is the point.