You are already a USC, so you don't need a green card. It would be a huge mistake for you to renew it since you are essentially stating that you are an LPR and not a USC.
File with what you have for US Passport. (Don't bother with the expensive N-600 which you will never need when you have a US passport.)
If you face a problem, explain that your green card was valid when your parents naturalized and on that day you automatically became a USC when you met the requirements of the Child Citizenship Act.
If your parents naturalized before you turned 18 and you were living with them in the USA at that time, you automatically became a USC and can get a passport.
