When can I amend my 2021 Tax Return with 1040X? I accidentally marked myself as dependent instead of independent and unfortunately my Federal Return was accepted. Help?

Can I only amend my 2021 taxes next year?  I didn't receive any of my stimulus checks as a result and was charged about an extra 1k because of this mistake.  I want to amend soon so I can get my money back.  When can I?