The phrase "first quarter of this year" refers to the first three months of 2021. It is a common way to describe the period from January through March, indicating that it is part of the current calendar year.
That was especially true in the tumultuous first quarter of this year. (wesmoss.com)
After the speedy first quarter of the year the world of online dating has finally dropped the pace. (skadate.com)
They had already planned to bring the tablet in first quarter of this year but as Microsoft launched its Surface tablet, they delayed the development of the tablet. (gadgetian.com)