Gamine and Ingenue are the two style essences that embody youthful beauty. If you are often taken for much younger than you are, you likely have a strong dose of one of these essences. But which one?
Clockwise from top left: Winona Ryder, Natalie Portman, Milla Jovovich, and (of course!) Maisie Williams all sell it as boys. Google these women, and you'll see they're flattered by Gamine styles.
Keira Knightley and Angelina Jolie, by contrast, couldn't really pass as boys:
(Although in each of their cases, I think it's both the lack of Gamine and the presence of Romantic that makes them fail this test. I don't think either one has much, if any, Ingenue either. That's mature beauty, there.)
I hope this helps those of you with youthful beauty sort yourselves out!
Have you tried the Style Identity Calculator?