My teenage daughter came home in tears because she was voted "Most shy" by the students for the school yearbook. I told her she wasn't a chatterbox and didn't feel the need to push to be the center of attention, but apparently she was popular among the students and they wanted to give her a special place in the yearbook. I think that made her feel a little better, but she was voted "most shy" several years in a row and I don't think she was ever really happy about it.
But, as you said, "Least likely to have children"...? That is just not right, even more so coming from the teachers. I definitely would have had something to say to the teachers and school if they gave my child an award like that.
How old was your daughter? I think most seniors in high school can handle it, but a 10 year old is pretty sensitive.
I'd say you handled that perfectly! :-) When people say "shy", they usually mean "nice, quiet girl." It's definitely a "most" to be proud of.