It's possible she used one of the various targeting/shortcut commands. <t> is your current target, for example, <tt> is your target's target, <f> is your focus, <me> is yourself, <r> is the last person to send you a tell, etc. etc. (There are several; I can't remember them all off the top of my head.) Or if she happened to have your name copied to the clipboard for something, she could have hit ctrl+v and pasted it in. Those are the two things that pop into my head, anyway.