The rule allowing people to forgo the 2020 RMD does not change the required beginning date, so anyone who had a required beginning date of April 1, 2021 still has that date, and must take their 2021 RMD by the end of the year.
However, someone who turned 72 in 2020 must have reached age 70½ before 2020. The change in required beginning date applies to individuals who attain age 70½ after December 31, 2019. Therefore, this individual had a required beginning date of either April 1, 2019 or April 1, 2020, depending on whether her birthday is in the first or second half of the year. Assuming it’s April 1, 2020 (in other words, her birthday is in the second half of the year, so she reached age 70½ in 2019), she’s in the same position as if the age 72 rule applied, because both her 2019 RMD (payable by April 1, 2020) and her 2020 RMD (payable by December 31, 2020) were suspended, and her first RMD must be paid by the end of this year.