If she meets the requirements to be claimed by you, then she can't claim herself even if you choose not to claim her. If she doesn't meet the requirements and you just claimed her by mistake, then she would have to file a tax return and not check the box that she can be claimed by someone else to file as independent.
She will probably not be able to efile the return since her name and SSN or on the return efiled by you on the non filer portal. If she can't efile, she will have to print and mail her return to get it accepted.
The IRS is way behind processing mailed tax returns and hasn't said when they will start processing them again. It may take months for her return to get processed.
While it is no help for you now, she can claim the stimulus payment on her 2020 tax return filed in early 2021. The payment is actually an advance on a 2020 credit.
