You didn't provide much information about your age, etc., but if you supported yourself 50% or more, you cannot qualify as your parents' dependent or qualifying relative. I'm assuming you're single and will file single. You must file your own return independent of your parents. It doesn't matter what your age is. Since your parents can't claim you, you should be eligible for the $1400 stimulus that was paid out around March 2021. If you didn't personally receive it, your tax return should show that you didn't receive one and you will receive the $1400 as a credit on your tax return. If your parents were awarded a stimulus for you as a dependent (based on their 2020 return), the good news for them is that they don't have repay it. The IRS doesn't want have to have to do a lot of "bookkeeping" on who might have received a stimulus payment they weren't entitled to.
