I believe that accurate knowledge is very, very important, but find that out in free time. Don't let it take over every hour of the day. Perhaps most important, talk about it.
I think the most important thing to do is to be willing to listen, willing to care, and willing to admit mistakes and change your ways for the better!
I urge you to read Eternal Treblinka and think deeply about its important message.
I think the most important thing is to keep active and to hope that your mind stays active.
You may not believe in evolution, and that is all right. How we humans came to be the way we are is far less important than how we should act now to get out of the mess we have made for ourselves.
Today it is generally accepted that although the earliest humans probably ate some meat, it was unlikely to have played a major role in their diet. Plants would have been a much more important source of food.
The most important thing is to actually think about what you do. To become aware and actually think about the effect of what you do on the environment and on society. That's key, and that underlies everything else.
Your life matters. You can't live through a day without making an impact on the world. And what's most important is to think about the impact of your actions on the world around you.