K.O.
I don't think it is weird either. As a teacher, I have tons of kids who are called by their middle names or even some nick name that is totally different (like Trey for the 3rd, even Junior) I can easily go along with this once I am made aware of it. However, you still need to realize that unless you legally change it, there is always going to be the chance of confusion. All school documents, and even the first roll call will be with her "given" first name (please make sure she knows what that is - it sounds crazy, but I have had Kindergarteners who can't answer, because they have always been called something different than there first name and they don't know their first name) Good luck with your decision.