The concept of "first tide" is a bit misleading. Tides are a natural phenomenon caused by the gravitational pull of the moon and sun, and they occur everywhere on Earth where there's a large body of water.

Therefore, there wasn't a single location where the "first tide" occurred. Tides have been happening on Earth for billions of years, since the planet had oceans.

Perhaps you're asking about the first recorded observation of tides? That would be much harder to pinpoint, as civilizations have been observing and understanding tides for millennia.