No. Since you did not indicate on your tax return that you can be claimed as a dependent, then your parents cannot claim you as a dependent on their tax return. If you incorrectly filed your tax return with the wrong dependency status, amend the return to change your dependency.
See this TurboTax support FAQ for amending a 2018 tax return - https://ttlc.intuit.com/community/amending/help/how-do-i-amend-a-return-in-turbotax/01/27579
Amended tax returns can only be printed and mailed, they cannot be e-filed. It will take the IRS 16 weeks or longer to process an amended return. Your parents can claim you as a dependent on their tax return but will only be able to mail the tax return since your tax return has already been accepted by the IRS with your current non-dependent status.
