Not physically, just that I have the same demeanor/look in my eyes. She said she'd always have to fill the role of big sister and keep him out of trouble etc, and that's what she feels is happening with me. He's 5 years younger than her, and I'm also younger than her. I know this usually screams friend zone, but I've had an ex girlfriend who compared me to her brother because we both had a quiet personality.
Should clarify that she doesn't "keep me out of trouble", but cares deeply about my wellbeing and doesn't want to see me get hurt etc.