Starting your 2019 tax return will not cause you to lose your 2018 tax information.  TurboTax will import your 2018 tax data into your 2019 tax return but this does not remove any data in your 2018 tax return.

I filed my 2018 taxes and never did finish, because i could not put in the correct amount due back for 2018

I also filed my 2019 taxes last year

I need to talk to  tubor tax expert.

@Discussme2 If you have the Turbo Tax Live product then you may schedule a call with your expert by following these steps; if you do not have this version, use the contact details found here.