It looks like there is more than one part to the question: a question about different historical ages on the Indian subcontinent, and a question about the Hindu idea of yugas, or ages. I’ll tackle the yugas first, then talk about the history.
A yuga in Hinduism is an “age” of time. There are four yugas: Satya, Treta, Dvapara, and Kali. The first age, the Satya, was a golden age, when everyone lived long lives and was happy and virtuous. In the next age, people are a bit less happy, live a little less, and are a little less virtuous. Same with the next age. In the last age, the Kali yuga, things degenerate, people are corrupt and lead short lives. This is the age we live in.
Now for their length: in the earliest Hindu texts, the first age lasted 4800 years; the next, 3600 years; the third, 2400 years; and finally, the Kali yuga should last 1200 years. Later Hindu texts multiply these figures, so often one sees the Kali yuga as lasting 432,000 years, the Dvapara yuga twice that, the Treta yuga three times that,and the Satya yuga four times that. And then they all cycle through again and again, so the world goes through periods of decline and renewal, age after age, for millions of years.
The historical and archaeological record shows that there used to be a thriving network of city-states in the Indus Valley region (in what is now Pakistan and northwest India). Sometime between 2000 BCE and 1000 BCE this civilization declined and the city-states were abandoned. Around that time, too, the first Vedic hymns were composed. The Rig Veda is generally dated to around 1500 BCE, for example, and this is the first evidence of the Sanskrit language in the region. From there the Vedic culture spread east and south throughout the Indian subcontinent over the centuries, and the religion we call Hinduism evolved.
That’s the history. Now some Hindus believe that there used to be a golden age in the past. Some say the Kali yuga began on 3102 BCE during the war that is central to the epic Mahabharata. They also say there were great cities with modern technology--stories of flying chariots are thought to represent ancient airplanes, for example. These ideas got a lot of attention in the 1990’s when a Hindu nationalist political party was in power in India, and sought to model their rule after some of these mythical stories.
There probably is not much evidence that there was such a golden age, nor is there any proof that the world moves in the yugas of the Hindu scripture. The Indus Valley civilization’s language remains undeciphered, so we can’t know what exactly is the relationship between their beliefs and those that came after. The date of 3102 BCE works astrologically, but archaeological evidence suggests that the events that the epic Mahabharata relates might have been a minor battle from around 900-800 BCE. At any rate, as for dating where we are in the age: If the Kali yuga started in 3102 BCE, then 3102 + 2010 = 5112 years into the Kali yuga. If we take the later figure of the Kali yuga being 432,000 years long, then we have a good 427,000 years or so to go before the end of the world and its recreation in the next cycle.