One year is real, but it does not necessarily start on January 1st. It’s just one whole orbit around the sun.
One day is real, but it does not necessarily start at midnight.
It’s just one revolution of the planet.
Everything else is imagined, no matter how much time we spend measuring with our watches and calendars.
So celebrate new year, but remember you could just as well do it on any other date, most appropriately on March 21st or September 21st at an equinox.