You have until May 17, 2024 to file a 2020 tax return for the Recovery Rebate Credit.
However, if you were being claimed as a dependent in 2020 you are not eligible for the stimulus payment.
You should also check your tax account to see if the IRS sent you the stimulus - https://www.irs.gov/payments/your-online-account
If you filed a 2020 tax return, they you will have to amend the 2020 return for the Recovery Rebate Credit.
See this TurboTax support FAQ for amending a tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-change-correct-return-a...
If you did not file a 2020 tax return -
To complete and file a 2020 tax return using TurboTax you would need to purchase, download and install on a personal computer one of the 2020 desktop editions from this website - https://turbotax.intuit.com/personal-taxes/past-years-products/
A 2020 tax return can only be printed and mailed, it cannot be e-filed using TurboTax.