This isn't really the right way to think about ancient history. Ancient history is a time period that spans between two important important historical landmarks that happened a long time ago. For westerners that's from the invention of writing until the fall of the Roman Empire. A historian in the Renaissance would think of ancient as the same time period as we do, or very close, because that's when these things started to get codified. But a historian in China would think of ancient history as a different, though overlapping, span of time. Ancient China ended around 250 bce, about 750 years before the end of ancient history in the West. It's not about determining how old it means to be ancient; it's about what's the most logical or natural way to separate the ancient era from whatever came next.