dependents

You have not provided enough information.   How old was she at the end of 2024?   Was she a full-time student in 2024?   Did she earn more than $5050 in 2024?

One thing we can tell you for sure---if she already filed a tax return that said no one can claim her, if you claim her and e-file, your e-file is going to be rejected, and you will have to file by mail.  And she will have to amend her tax return.

IRS interview to help determine who can be claimed:

https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent

WHO CAN I CLAIM AS A DEPENDENT?

You can claim a child, relative, friend, or fiancé (etc.) as a dependent on your 2024 taxes as long as they meet the following requirements:

Qualifying child

• They're related to you.
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They're under the age of 19 (or 24 for full-time students).
• No age limit for permanently and totally disabled children.
• They lived with you for more than half the year (exceptions apply).
• They didn't provide more than half of their own support for the year.

Qualifying relative

• They don't have to be related to you (despite the name).
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They lived with you the entire year (exceptions apply).
• They made less than $5050 in 2024 (not counting Social Security)
• You provided more than half of their financial support.

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them. There may be other tax benefits you can get when you claim a dependent.

It depends.

If she is under 19 (or under 24 and a full-time student), then you can claim her as a dependent. If you do, you cannot e-file and have to paper file as she said on her return that no one can claim her as adependent. She would also need to amend her return to state that she can be claimed as a dependent.

If she is 19 or older (or 24 or older and a full-time student) and has gross income of more than $5,050, then you cannot claim her as a dependent.

Please read this TurboTax article for more information.