Of course life could have existed elsewhere in the universe long before the Earth came into existence. There is no reason to think that the life creating events that occurred on this planet could not have occurred elsewhere in the past. The universe is more than three times older than the Earth, that is a lot of time for some other planets to get going.
It is very possible that there was life before earth. We are on the brink of our Earth ending and perhaps there will be a new life force after us. If you are thinking of the Bible, God destroyed the planet once. Was it Earth? Was it even given a name? The "planet" God destroyed proved through the Bible that there was life before "Earth."
Earth is over 4 billion years old. The Universe is an estimated 13.82 billion years old. The oldest planetary systems are are 12.8 billion years old. Life could have existed elsewhere in the universe, though I won't speculate on the nature of that life or its level of sentience. Bacteria is known to survive some very extreme conditions, so it is very feasible that some level of life could be found in the Universe long before the Earth was formed.