If you were due a refund (with the numbers from Mom's W2), wait for the return to process and for the refund to happen. Then file an Amended return. Last thing I knew TT only allows amended returns on paper (i.e. mail in to the IRS) and the IRS started the season with 5Million paper returns from 2020 taxes unprocessed. So, an amended return filed on paper probably will take months to process. The IRS has allowed some of the big tax prep companies to file amended returns electronically. Weigh what it would cost to go to one of these companies to build your original return from scratch (they have to do it just like you did) and then add the amended return form 1040X and then make the corrections. They will probably charge you something approaching their fee if you had gone to them originally, and maybe more. But it will process MUCH faster if the amended return is filed electronically. You could just wait for the IRS to figure out your mistake, but it might take months and if you got a bigger refund (using Mom's data) then you were entitled to using your own data you could face penalties and interest for filing a 'false' return.
Edit: Looks like some platforms of TT may allow the electronic filing of a 1040X (probably not the free version). So, upgrading (a favorite TT gambit), or opening your saved file in a different TT platform and then doing the 1040X. Can't find clear knowledge of which platforms (online, desktop) etc allow for efiling of the 1040X.
