Christians don’t believe in a created God, we believe God is infinite – he always was and will always be. Watch God’ Not Dead – Josh does a good job of answering that question.
Also, the Bible says God created the earth in 6 days and rested on the 7th, but no where does it say 6 24hr days. A day on earth isn’t the same as a day in Heaven. The bible never specifically says how long a day in Heaven is, Jesus only made a reference as part of an analogy but that doesn’t mean it was absolute but rather a way of showing time in Heaven is basically meaningless when he said a day in Heaven is like a thousand years on earth. So, when God created the world in 6 days – it’s 6 days as HE defines them, not us, and we don’t know how long that actually is.
Only problem – Noah was on the ark for 7 days before the rain began.