I am in charge of my peace. I protect and take care of myself at all costs.

Protecting your peace almost always means disappointing somebody. That is the cost the phrase is quietly referring to.

It looks like leaving a party at nine. Like not answering the group chat until morning. Like a no delivered without the paragraph of justification you feel obliged to attach.

Most people are far more comfortable being tired than being seen as difficult, and they trade sleep for approval for years without ever naming the exchange rate.

Being in charge of it means you set the price, rather than apologizing afterward for having charged one.