Are you a high school student?

Yesterday, as I was leaving school, a woman outside the school gates gave me a flyer for a salon d'étudiants.  I looked at it, handed it back, and politely informed her that I am not actually a student.  She looked so incredibly mortified to have mistaken someone on staff for a high school student - her expression and hurried apology were really quite humorous. I just tried to hide my laughter (unsuccessfully) and hoped none of my students saw. Although I supposed they don't need anyone to tell them I look young - I'm sure they've noticed.