AITA for pulling out of planning my sister's wedding, causing her to lose her venue?

As a wedding planner who has been in the industry for many years now, my (31M) party trick amongst close friends and family is being able to guess how long my clients' marriages will last with pretty alarming accuracy. If you ask anyone in the industry, there are specific indicators while working with a couple that allow us to be able to gauge compatibility. I can usually get down to around a six month window when predicting when photos of each other will disappear from socials.

This is not me taking joy in crashing and burning of relationships. Working in this career field can actually leave you feeling jaded about relationships in general, which is why I'm reluctant to work for friends and family. The specific stress wedding planning puts on some people/couples can bring out the worst in them that you don't see in everyday life.

My sister is getting married early next year and practically begged me to plan for her despite my stance on clients I know personally. I finally gave in and we began the process back in March.

Last week, while we were meeting and finalizing a few things, she asked me about the party trick I mentioned. She said since I had been working with her and her fiancé for months now, I could give my prediction as to how long they were going to last. I laughed and tried to move on. I thought she was joking, but she continued to press the issue. After her continually bothering me about this for at least 15 minutes when I'm trying to move on (I do have work outside of my specific appointment with her that I needed to get to), I finally told her I thought they would last forever. She claimed she didn't believe me and wanted my real number, so I shrugged and told her the truth: A year and a half.

She was livid. I felt incredibly uncomfortable with the whole ordeal, especially with how little she respected my boundaries in what is supposed to be a professional setting, and just tried to usher her out of my office. Instead, she began ranting about my own marriage and said she gives us until the end of the year before we break up, and accused me of being a homewrecker.

She finally left, and I emailed her saying I would no longer be involved in planning. I gave her the contact information for all of the vendors we were working with, but told her the venue would no longer be available as they only book to people they have existing relationships with and my involvement was necessary. I have had to "break up" with clients before, but this felt particularly rough.

She is now told our parents that I am purposefully sabotaging her wedding, and that I was unforgivably rude to her when she just asked a playful question. I feel very silly for letting a person disrespect my boundaries over and over again, something I typically wouldn't tolerate, but now I'm wondering if I'm in the wrong.

AITA?