Generally, when a statement hurts the recipients feelings, it has elicited some (at least subconsious) sense of guilt or shame.
In this case the girl is clearly formally giving you a complete message of crap that realistically should be easy to just laugh off. But obviously you could not.
Hence, with the typically well evolved capacity of teenagers, she managed to hit a 'nerve'. As your reaction in this case is based primarily on a subconscious compilation of reasons, you feel hurt and mal treated but you can not understand why you should (she is just an imbecile kid, who cares right).
You have been a target for the paradoxical situation where you formally have done nothing at all that should render such aggrevation on her part - yet your subconscious canīt but to feel she in some perverted way has a point. That is why you are upset enough to post the event.
Now if this post is not qualified, nonsense, ranting - I donīt know what is!