I'm filing the final return for an estate. Turbotax automatically selects short year. Is this required or can I change to calendar year?

Yes. It is required. 

IRS says: A short tax year is a tax year of less than 12 months. A short period tax return may be required when you (as a taxable entity):
 

• Are not in existence for an entire tax year, or
• Change your accounting period.

Tax on a short period tax return is figured differently for each situation.

Not in Existence Entire Year

Even if you (a taxable entity) were not in existence for the entire year, a tax return is required for the time you were in existence. Requirements for filing the return and figuring the tax are generally the same as the requirements for a return for a full tax year (12 months) ending on the last day of the short tax year.

For more information, see Publication 538, Accounting Periods and Methods

See Tax Years

What is critical is filing the return on a timely basis, which entails filing the 1041 by the 15th day of the 4th month following the close of the tax year.

See https://www.irs.gov/instructions/i1041#en_US_2022_publink1000285977