It’s hard to know the answer to this question, mainly because we have to figure out what we mean by “person.” Does it count if the “person” looked like us? Did they have to be as tall? Did they have to be as smart?
We may not ever know who the first person on earth was. But thanks to lots of careful work, we may someday learn out about the first *groups* of people on earth!
Jonathan is right. We can’t really know with certainty who was the first person. Often people talk about “Lucy” a 3.2 million-year-old hominin (human-like primate) that was discovered. Recently they found bones they believe to be even older: http://www.bbc.com/news/science-environment-31718336 It’s all relative to the oldest sources we find for information.
The first population of modern humans is estimated to have lived about 200,000 years ago. When we think of species, we always have to think in terms of populations, not individuals. Mutations occur in individuals, but populations evolve.