Bear with me on this and think about it. It's not a dumb question but...
Has World War Three already begun?
Formal declarations of war are consigned to history books whether we like it or not. Cyber warfare, proxy wars, disputed territories, displaced peoples, genocides.
There is a lot to consider right now and the "sides" seem to be most of Europe and North America vs. Russia and China with other players like Iran and Saudi Arabia. It might not be open warfare but it could be considered warfare.
If I was to speculate, I'd say somewhere between 2008-2014 is where it really went up a gear.