Well I wouldn't say it's peaceful now, or has been in the past... Actually there's few years that the US wasn't at war.
Compared to the time of great powers before WW1 and during, this has been by far the most peaceful the globe has been for a very long time
The entire Iran "war" will probably have less casualties than a single day of World War I.
Please, for the love of God, speak to someone who is actually from a war torn country and understand how privileged all of us have been to live in the west. Even the wars we have been part of in the middle east have been minor disruptions to the Pax Americana: we really don't feel the effect of the wars we are in.(another problem in of itself).
99% of us got to grow up without the fear of military violence, and go about our lives.
The world /is/ peaceful right now... relatively that is.
Not to say there isn't war, but they're small wars with a million deaths being a big one.
More people died in Second World War[1] than in all wars since then combined. If not for the Russian Civil War and WW2, the same would probably true for the Great War.
War is terrible, but the fraction of people who died in wars the last 75 years is substantially smaller than the 75 years before that and I do think that is worth celebrating. I am not confident this will hold for the next 75 years
[1]: https://en.wikipedia.org/wiki/List_of_wars_by_death_toll