People born in 1951 take the first RMD in 2024. The first one can be postponed until April 1 of the following year.
Participants in a work-place retirement plan (401K, profit sharing) can delay the RMD until they retire unless they are a 5% owner of the business sponsoring the plan.
For an IRA inherited after 2019 usually you must have it distributed within 10 years.
More details, including exceptions for surviving spouses or minor children who inherit retirement plans.