Medieval level world... with zippers.
Zippers are from the Industrial age. Without machine manufacturing, someone would have to
hand-craft every single zipper tooth. Then every single tooth would have to be precision placed onto the fabric.
Even if zippers somehow existed in a medieval age world, they'd absolutely be seen as a status symbol due to how expensive it would be to create a zipper that functions smoothly and flawlessly every time. The moment people see a zipper on your clothing, they'd instantly know "This person is rich as hell"... so there's no way MC could pretend to be a newbie adventurer with zippered clothing.