Why does Samuel prophecy this now? Helaman 13

Why does Samuel prophecy this now? Helaman 13

It puzzles me that Samuel prophesies to the wicked Nephites, calling them to repentance, 6 years before Jesus Christ was crucified and came to the American continent after he was resurrected.

But perhaps it shouldn't puzzle me too much. 6 years is enough time to repent. I bet that some people, perhaps the people who heard Samuel's prophesies and wrote them down, were able to repent and change their lives around in that time frame. Maybe God doesn't call prophets to cry repentance without giving the people to whom they preach a little bit of time to change.

Or maybe it just depends on the situation.

Answer:
Because that was what God wanted.