My daughter marked she could be claimed , she wasn’t can she change this and still get a stimulus check ?

the issue isn't WAS SHE claimed, it's CAN SHE be claimed. 

see the difference? 

COULD YOU claim her? whether you did or not is immaterial

here are the eligibility rules:

A1.  You may be eligible to receive a Payment if you:

• Are a U.S. citizen or U.S. resident alien;
• Cannot be claimed as a dependent on someone else’s return;
• Have a Social Security number (SSN) that is valid for employment (valid SSN); and
• Exception: If either spouse is a member of the U.S. Armed Forces at any time during the taxable year, then only one spouse needs to have a valid SSN
• Have adjusted gross income below an amount based on your filing status and the number of your qualifying children.