If you can be claimed as a dependent according to the rules, you must check the box that says you can be claimed even if you don’t want to be claimed as a dependent. If you believe you cannot be claimed as a dependent, you will have to file your return by mail. The IRS will be very backlogged because right now they are not processing paper returns, but eventually they will see the duplicate dependent claim and they will send letters to both you and your parents asking for proof of your circumstances. Whoever filed incorrectly will have to pay back any tax benefits or credits, with interest and possibly penalties. So before you file a tax return that conflicts with your parents, make sure you really know what you’re doing.
In any case, you will not qualify for a stimulus payment now if your parents claimed you as a dependent.
The stimulus payment is technically an advance payment of a new credit that will be on the 2020 tax return. If you qualify for the credit when you file your 2020 tax return, it will be added to your refund then, if it was not paid to you now.
