The former O.C. star landed at Los Angeles International Airport (LAX) when the embarrassing incident occurred and the 31-year-old actress is worried her youthful looks will one day become even more of a hindrance.
She tells Women's Health magazine, "I know I look super-young. I was flying home into LAX the other day and the security guard at the airport stopped me and said, 'Honey, where's your family?' - I'm 31.
"Maybe when I'm older I'll appreciate it but as I get older and get wrinkles I'm worried it'll be, 'She's the weirdest looking teenager I've ever seen'."
Bilson is not the only actress whose appearance has caused a mix-up at airports - Harry Potter star Emma Watson was mistaken for an unaccompanied minor last year (12) at John F. Kennedy International Airport in New York.