If Allah S.W.T created us so he created our brains which will determine our acts and our decisions, then why we will be punished for our mistakes?

I can't stop thinking about that question since i first has been asked it from an atheist. I am a Muslim and I believe none has a 100% belief in Allah s.w.t even me, and that is because the logical questions that come to our minds from time to time. Then I decided to try atheists' questions, and see their answers or try to answer it in order to clear all these questions to me to reach 100% certainty in Allah.