So if you google it you will find that life expectancy in the ancient world was around 20-30 year of age. But that is super misleading.

That number is the life expectancy at birth, and includes the high mortality rates of infancy and childhood. For example, in ancient Rome if you lived past ten then life expectancy increased to around fifty years. If you lived to fifteen it increased even more.

A lot of what I have read recently seems to indicate that if you lived past fifteen in the ancient world then you could probably expect to live into your sixties assuming you were not killed in war or by the plague.

So while modern medical advancement have certainly increase how long a person will live, most of the change from the 25 -> 85 life expectancy comes from our greatly improved ability to prevent infant and child mortality.