The only way you can file your tax return is by mail. Even if your mother amended her return, your SSN is in the system for this year. Her amended return will never "catch up" in order for you to e-file.
When you mail a tax return, you need to attach any documents showing tax withheld, such as your W-2’s or any 1099’s. Use a mailing service that will track it, such as UPS or certified mail so you will know the IRS/state received the return.
Federal and state returns must be in separate envelopes and they are mailed to different addresses. Read the mailing instructions that print with your tax return carefully so you mail them to the right addresses.
Amended returns take at least 4 months to process, so hers has not yet gone through the system. You will have to print, sign and file your own return by mail.
But be aware that, if you qualified to be a dependent in 2020, you are not eligible for stimulus. It doesn't matter whether Mom actually claims you or not.