My school had a test and then you got put in a special class and had individualized education plans you had to do every trimester. I think it was about 5% of the school. If your state doesn't have this program I could see it coming off as weird/made up/something only internet people say (because the internet people had the program and the people around you didn't).

You can search for gifted and talented education to find the kind of program I'm talking about. It isn't kids or parents deciding they're gifted but the school telling them they are.