Did your parents file a separate tax return for any income you earned?
Yes, my parents did (I’m their dependent).
You’re misunderstanding. People are asking if a return was filed specifically for you. If so, check that it doesn’t accidentally say you’re not a dependent. This small mistake is usually the issue.
You’re doing all the right things by freezing your credit, adding alerts, and setting up an ID PIN.
I’d suggest also getting copies of your credit reports and ChexSystems/Early Warning reports. Adding a fraud alert on ChexSystems is a good idea too. If you find any accounts you didn’t open, file an ID theft affidavit and maybe a police report.
It’s also possible someone else typed in your SSN by mistake.
Regarding the notice itself, there’s nothing to worry about if your parents used the correct info and you can be claimed as their dependent.
The main focus should be preventing this from happening again, and you’re already handling that well.