I never thought of myself as a redhead growing up because I never had that classic flaming hue, but everyone kept calling me one. My hair was more auburn as a kid, strawberry blonde as an adult. People called me out as a redhead even when I was wearing it a different color (blonde, brown).
I think your complexion has a lot to do with your hair color in general, and can say a lot about your hair's undertones, even if they're not visually obvious at first.