It's important to note that this countdown is far from being official. I got the data from windows 10 end of support documentation, there is no data for IE11 specifically. IE11 might stopped being supported by microsoft sooner or later than this date. The good news is that you don't have to wait for this countdown to reach 0 to stop supporting this archaic browser. As you can see in the Who stopped supporting IE11 section, there many companies and websites that didn't wait.
If you want to add A reason or your website, this is how.