I kind of answered this in my old timeline thread:
"All three Sannin were 6 years old when they first became a part of Hiruzen's team, which is right after they graduated the Ninja Academy. That would be 48 years ago. It is also said that Hiruzen was already Hokage when the Sannin became part of his team. Hiruzen would have been 21 at that time. We know when Hiruzen became Hokage, it was during the battle in the First War when Tobirama became the decoy and sacrificed himself so that Team Tobirama could live. So he had to have become Hokage sometime before he was 21. We know he was in Team Tobirama when he was little with Homura and Koharu:
(Picture of Hiruzen as a child with Tobirama goes here, link from my old thread is dead)
They were both a few years older than Hiruzen, so I am speculating that they were 10 years old when they graduated the Ninja Academy and concurrently went into the team, and that Hiruzen was about 6 or 7, and the war was not going on then. I would imagine Hiruzen was about 17 or 18 when he became Hokage that say that Tobirama died. I cannot see him being really any younger, since that would odd for someone even younger than that becoming Hokage. So that would mean the War was about 52 years ago. Another point is that IF the War was indeed 52 years ago, there is a scene where Hashirama was with a child Tsunade, so that scene would fit the timeline of events. Tsunade would have been 2 years old when the war happened, so Hashirama could have indeed been in a scene with her before the war according to this. Note: Danzo would have been 20 during the battle Tobirama died, and Kagami would have been around the same age, probably 18-20.
Now Hashirama was his older brother, so he had to have been a little older than Tobirama, I would say at the most he was 5 years older. So that means he would be 82-95 years old today. Hashirama trained Hiruzen also, so he was definitely alive some time shortly before the First World War. That would mean Hashirama and Madara fought in their epic battle when they were 30-40 years old most likely. "
Hiruzen was 68 or 69 when he died, Tobirama would be 82~92 years old today. Tsunade is 54 today(same with Jiraiya and Orochimaru). So it works, at least with the gambling part, Hashirama knowing about her strength is kind of weird though, but who knows maybe she was strong even as a 5 year old or something. I think Tsunade was only born 2 years or so before the start of the first war, so Hashirama would have still been alive, since he was alive shortly before the first war. Anyway, needs updating since I wrote that a long time ago, and some things weren't revealed yet.
