Who created God?

Christians don't believe God was created. They believe he's the one thing that has always existed, with nothing before him and nothing that made him.

That's not a trick answer. There's a difference between things that had a beginning—which do need a cause—and something that never had a beginning at all.

The universe did have a beginning. Its matter, energy, space, and time all started at some point, and none of it had to exist. Christians say God is different: he didn't start, and he doesn't depend on anything else.

So asking "who created God" assumes God is like the universe—something built, one piece causing the next. Christianity says something else: every chain of "what caused this?" has to end somewhere, in something that simply always was.

That doesn't prove God is real. But it shows the question, asked that way, misunderstands what Christians mean by "God."