Would this get you mad if you found it on your bfs facebook?

I would be mad at the girl, but proud of ur bf. Your bf was really clear with this girl that he was in a relationship with you. The fact that he even told her how long you have been going out without being asked is a sign that he really does care about you. It seems to me that your bf is just trying to deal with this girl who is hitting on him, without seeming like a jerk. He is keeping things really casual in this conversation, while the girl is acting way too flirty toward a taken guy.