Was she childish and mean for telling me this?

We've dated on/off and got in a fight a month ago over her pulling back physically. She remained distant so I backed off. Games ensued; she'd send blank texts, text normalyl then pull back, etc. Things seem mostly back to normal and we have plans for Tuesday for the first time since the fight. Texting today, she asks if I have any plans: I tell her work, meeting someone for coffee then drinks with friends. She replies saying she's cleaning her apartment, and might have Danny over for dinner. Well, Danny is an ex-bf and she mentioned in the past he is sometimes a friends with benefits. I was outraged she'd tell me that. Didn't respond to the text and it makes me want to blow her off Tuesday. Am I over reacting, or was that pretty low on her part?