Yes it is. According to this story using a biological analog of something called "Moore's Law" we can date the origins of life:
Moore's Law is the observation that computers increase exponentially in complexity, at a rate of about double the transistors per integrated circuit every two years. If you apply Moore's Law to just the last few years' rate of computational complexity and work backward, you'll get back to the 1960s, when the first microchip was, indeed, invented.
So even if it's mathematically possible for life to have existed before Earth did, is it physically possible? Again, Sharov and Gordon said yes, it is. As our solar system was forming, pre-existing bacterialike organisms, or even simple nucleotides from an older part of the galaxy, could have reached Earth by hitching an interstellar ride on comets, asteroids or other inorganic space debris — a theoretical process called panspermia.