Which decade of the 21st century have we been going through? The zeroth? Zerost? Zerond? Zerord? Or the first?
While I find calling the years 2000-2009 “the Oughts” to be awkward, and the next decade “the Tens/Teens” moreso, I hope that in 2030 we don’t see a bunch of people saying that it’s still “the Twenties.”
Saying that it is still the third decade of the Twenty-first Century will be acceptable, and correct.