I thought you were put on earth as a either a kid or grown-up.
A childhood belief about getting older

others believed things like this
- I thought grown ups were born grown ups.— mea
- I used to believe that grown-ups were born "grown up" and that I would stay a little kid forever.— Still A Kid
- I used to believe that grown-ups were born grown up.— Juleen
- When I was a child, I thought that grown-ups were adult.— Gloria
- i thought grown ups read in a different language!Anon
- When I was little I thought grown ups could fly but wouldn't tell me about it or teach me until I got older.— James the Great