So, it all started last summer when I asked out this girl, A, and got rejected: no big deal. However, from there we started texting and meeting up, and became good friends, completely platonically. (all of my friends know this)

This year I discovered that me and a girl, B, both have feelings for each other, which was cool. A few days ago however, A asked if I wanted to meet up on Thursday (not as a valentine, it's just we were both free that day.)

Today, I mentioned in passing to a "friend", C, my plans for Thursday, (Keep in mind that I had had no contact with B, and had definitely not been asked to do anything on valentines by her,) and was told that I was being stupid by C, and that B would be angry. I took it with a pinch of salt, as he is one of B's close friends, and want us to get together, but not before asking him not to tell her, to which he promised. I pretty much ignored it until a few hours later, when mutual friends all begin to chime in, supporting C. I asked C how they knew, and he told me that he had "accidentally" told them. (I later discovered that he had immediately pulled B aside and told her upon seeing her, and had gone on to tell others in the group.) Just now however, he sent me a screenshot of a conversation he'd had with B, where she mentioned that she'd be "fuming" if she had found out any later, or from someone else. In my opinion, she, and C, had no right to be upset at all, and my meeting A will have no bearing on any interactions that I might have with B in the future, yet judging by my friends reactions, I feel like I'm missing something. So, AITA? 