I do not look 18. At least I didn't think so...

I was helping a woman in the library on Friday who pretty much needed her hand held while she went online. I was talking her through what to do on some sites, so I knew she was looking at job search sites. She was getting frustrated, and I told her I understood because I had just graduated in December 2007 so knew what the job search process was like. She replied, "Oh, did you graduate from college?" I was about to say "grad school" when she continued, "Or from high school?" Now I'm fully aware I look younger than I am. My mom is the same way. (I hope I look as good as she does when I'm her age!) I can see why someone might possibly mistake me for a 22 year old. However I cannot see how I could possibly look 18! MAYBE I could see it if I was wearing jeans and a t-shirt, although I still think that would be a stretch. However in this instance I was wearing a nice skirt an shirt for work. When I told her I was 27 she was shocked. She seemed like a very nice older lady (who needs lots of help online), but I'm still surprised she thought I might have just graduated from high school.