AITA for being upset after my sister in law announced my wedding?

This happened a few weeks ago. I (f33) and my fiance (m32) will be getting married in November next year, we´ve been together for almost 14 years at the moment.

We told our families (parents and siblings) about the wedding so they can be excited with us about the wedding. But I told directly to my sister in law (f37), that we do not want to annouce the wedding to the rest of the family just yet, as another of her brothers just got married last november and I felt it was too close to theirs, and too far from mine to announce it just yet.

A few weeks pass by after we told them, and my fiance was hanging in his mother's house (I was at our house), and there were some of his aunts and his grandma. When my fiance come back, he told me that his sister insisted in front of the family to "tell them the news" and he ended telling them about the wedding.

I was furious, since I wanted to do the announcement together, not just after some pressure from his sister (he acknowledged later that he should have been firm with the choice we made, but I understand too, that his family begin to push after her sister and it's kinda hard to keep the information to himself).

Once I was calm, I sent a text message to her sister, letting her know that I was upset, because I already told her we wanted to wait for the announcement, and she shouldn't have insisted, and it isn't her place to announce it (I even made my husband read the message to make sure I was not offending and it was in a good tone, he's much rational than I).

Long story short, she got upset for telling her that, and she is going NC with my fiance, daughter and I. She usually doesn't lasts angry this much, that is why I'm now wondering if I was TA