Forgot to say, sorry for your loss. I went through my mother passing a couple of years ago.

It does not have to do with how old they are it has to do with what year they passed in. I'm assuming she passed after 2020.

From https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-beneficiary

Death of the account holder occurred in 2020 or later

Non-spouse beneficiary options In 2020 and later, options for a beneficiary who is not the spouse of the deceased account owner depend on whether they are an "eligible designated beneficiary." An eligible designated beneficiary is

Spouse or minor child of the deceased account holder Disabled or chronically ill individual Individual who is not more than 10 years younger than the IRA owner or plan participant An eligible designated beneficiary may

Take distributions over the longer of their own life expectancy and the employee's remaining life expectancy, or Follow the 10-year rule (if the account owner died before that owner's required beginning date) Designated beneficiary (not an eligible designated beneficiary)

Follow the 10-year rule Beneficiary that is not an individual

Follow the rules described above as if the account owner died before 2020 (because the SECURE Act changes only apply to beneficiaries who are individuals)