Hopefully we are able to use our willpower to bring about personality change over the course of our life.
There are people with unusual levels of willpower. I am one of them and I know others. It is what it is.
You can learn new information, and you can adjust your behavior or habits based on that.
The new things you learn wouldn't have been inside your DNA/genes.
Regarding learning new information, surely the type of info you’re susceptible to, and how to act upon these, isn’t all of your choosing.