It could be that your overall appearance, including your looks and the way you present yourself, has elements that remind people of characters in manga. Maybe it's your colorful and stylish outfit or a certain pose you strike that gives off that manga vibe.
It could be a combination of factors like distinctive clothing, hairstyle, or even the way one carries themselves that makes them seem manga-like. Maybe it's their big expressive eyes or a certain charm in their demeanor.