If you e-file for the 2019 tax year right now and answer the question of whether or not anyone can claim you as a dependent as "no". The system will quickly reject your return if someone has already claimed you as a dependent for that tax year. This happens in less than an hour typically. That's assuming they already filed their 2019 taxes and claimed you as a dependent.

However, the message you get back from the IRS through your tax software or website says that if you refile and don't change the answer to the question then the IRS will contact both you and your parents by phone to try to clarify the dispute. Should you and your parents both tell the IRS that you shouldn't be claimed as a dependent then I believe you could be eligible for a stimulus check in 2019, but they would lose the value of whatever deductions they were able to make by claiming you as a dependent. Those deductions were probably worth more than 1,200 dollars to them.