Konoha was founded during the warring clan era by Hashirama and Madara. Now to have the power and get acknowledged by the other clans to create konoha they have to have been somewhere between age 25 to 35. Hashirama's brother, the 2nd hokage, would have been around the same age too.
In a flash back we can see that the 2nd hokage was just around 30 years old when he was killed by the gold and silver brothers.
And the 3rd hokage has been his disciple since being a genin. From this we can say that konoha was created just around the same time as when the 3rd hokage was born.
And he was 68, i think, when he was killed b the snake sennin. Add another 30 years and when boruto takes place the village is just around 100 years old. It may seem like the village is older when in reality it is not. Everything in the ninja world just changes too quickly.