How could God exist before space was created since there would be no place for him to exist?
I guess "in the beginning" means the beginning of our universe. That's where the Bible starts. There's no mention of what was happening before that.
Besides all the really cool stuff happens later. Jonah gets swallowed by a whale and lives inside it. Noah lives to be 400 years old, then builds an ark and sets sail with a floating zoo while God kills every living thing on Earth. To force a Pharoh in Egypt to release his slaves God sends an Angel to kill children. (Seems if He could create a universe dealing with one little Pharoh would be a snap.) God turns a lady into salt for looking over her shoulder and He ruins a man's entire life to settle a bet with Satan.
On and on it goes.
Google that question. There are theories, but no one really knows. You are correct when you say space would not exist and that there is no "outside", at least not in the three dimensions we understand.
If you go through the Bible, beginning with Genesis, and count through you come up with an age of 6000 years. It's ridiculous.