The notice has nothing to do with the license. You just write who holds the copyright. If you don't use code written by someone else, your name is enough.

Many licenses like GPL need copyright to be specified. Regardless, copyright statement won't affect how you license the content.

First, the copyright notice doesn't really do much. Any copyright status, licensing, etc apply whether or not there's a notice.

Second, if you created it, you have full control on how you license it. You can even use multiple licenses. It's common to have GPL (or similar) for personal use, and commercial use being licensed separately for a fee.

If you didn't create it (other contributors did), then each contribution is owned and copyrighted by each contributor. Presumably they have licensed their works under the GPL.

Do you have a specific reason to even include a copyright notice?

If it is your project, no need to get headaches about this. However keep for example the stuff like “Copyright YEAR - your-name” and say it’s under GPL 3 license. But nothing more.