AITA for going against her wishes?

About 4 years ago, I had finally gotten my first girlfriend (I was a sophomore in high school, as was she). I had known her for so many years, since kindergarten. We were both pretty nerdy, so we were both rather shy.

Sadly, I didn't get to talk to her as much because of marching band practices after school. But after a while, whenever I would get to see her, I noticed she was really stressed. I mean REALLY stressed, to the point of her hair thinning and such. She was smart, so I didn't think it was just school.

Then she told me a story of her father getting angry and she ended up being shoved into the stove, bruising her hip pretty badly (she was naturally thin). Of course, I expressed my concerns for her health but she kind of brushed it off. I kept noticing things that looked and sounded like she was being abused by her father.

Eventually, I just had to do something. I hated seeing her so stressed and hurt. I went to a teacher I trusted and told him the situation, and encouraged me to go to the guidance counselor, which I did right then. This was INCREDIBLY uncomfortable for me, way outside of my comfort zone.

When I had mentioned telling someone about her issue, she got kind of angry at me. But here I was, telling a counselor about her signs of stress and bruises and such. I did make sure to say I never was 100% sure there was abuse, but signs pointed to it. I was told they'd bring her in and talk to her.

Then the next day comes. I'm nervous all day because I knew she was going to be asked about it. After school... Yeah. She was very upset with me. Somehow, she didn't outright break up with me, but she would barely even speak to me. I ended up breaking up with her (though it was more mutual at this point).

And then, as if I didn't feel bad enough, my friends told me that she was flirting with someone near the end there, and she actually gets together with this guy less than a week after we break up.

I was never really told if there was abuse, if anything was done, anything. I may have just made her mad at me for no reason whatsoever. To this day, I still haven't felt justified in my decision to go to a counselor. I really, really feel like the asshole.