The Infinitely Old Universe

How old is the universe? Our bubble universe is though to be the product of the Big Bang about 13 billion years ago. But the greater universe, in which ours is just a tiny drop in an infinite ocean, is thought to be eternal. We'll probably never know this for sure. According to Alan Guth: "In an eternally inflating universe, anything that can happen will happen; in fact, it will happen an infinite number of times".