Nah. A decade is a period of ten years. If you’re ten years old you’re a decade old. The 2020s is a ten year period that starts on 1/1/2020 and ends on 12/31/2029.
If you said the 202 decade of the modern are doesn’t start until 2021, I could get behind it. But Decade in general is just a ten year period of time. It starts and ends depending on when you choose.