Mankind is ca 3.4 million years old, homo sapiens sapiens ca 200,000 years old.
How old is justice, would you say? Did it exist before life on Earth or did humans create it? Is it something real or just a system of conduct (like using names or money)?
Mankind is ca 3.4 million years old, homo sapiens sapiens ca 200,000 years old. Says who? Well, it's what has been deduced from evidence of and surrounding what objects and materials hadn't degraded into formlessness over the course of millennia: fossil records and carbon-dating, to be a little more specific. While the meaning of "homo sapiens sapiens" is very technical and exact, the meaning "mankind" is muddled to a significant degree, but it as a category is understood to encompass "homo sapiens" among other branches of the overall family tree of "human" or "primate" life.
Justice happened when the first person felt wronged and took action. Its hard to trace when it may be as it would be within the first couple generations after creation.