The very fact you’re interviewing face-to-face means you passed the code challenge, the next step is to make sure you’ve come prepared with a rationale for the decisions you made and be ready to talk them through. “Oh, I wrote that? I don’t remember”, could lead to some difficult moments. While it’s unlikely you’ll be expected to write out perfect code on a whiteboard (many developers use IDEs and this is a reasonable mitigation for imperfect syntax), being able to justify your choices and the ability to rationalise and compare alternative solutions is particularly important in agile development teams.