need to amend my tax return because I'm claimed as a dependent on my mom's return. How do I change that

Before starting to amend the tax return, wait for the tax refund to be received or the taxes due to be paid and processed by the IRS.

See this TurboTax support FAQ for amending a current year tax return - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-return/amend-federal-tax-return-current-year/L7eS6o1qh_US_en_US?uid=lfunevhk

You edit your personal information in the My Info section of the online TurboTax program.  For being claimed as a dependent, it will be on the screen Let's Check for Some Other Situations.