Good that you are discussing with others outside your faith. learning about other beliefs and atheism is a good start to find the truth. what you learned from your parents may not be the truth. Even the quran talked about ancient people rejecting prophets using an absurd argument "we will just continue the religion of our fathers. even if your fathers were ignorant?"
بل نعبد ما وجدنا عليه اباءنا واجدادنا. اولو كان اباءكم لا يعقلون؟
God existence as described by Islam or Christianity is not self evident. it makes no sense and it is self-contradictory. There maybe a god or thousands of gods. or maybe not. There is no enough proof. The quran claims the fact that life is complex as proof that allah is our god and then claims that allah sent us prophets and books. I can claim complex life is evidence of a unicorn or Hubel, allat or Zeus and will be the same amount of proof.
This subject is long and hard to put everything here. I encourage you to learn more. learn about other religions and science. I was like you once. The quran doesn't know much about Christianity because Christianity wasn't common in Mecca and Medinah. Quran knows more about Judiasm because there was a large Jewish presence in Medinah. I encourage you to learn about Christianity. It's the path to reject both.