Possible “bridezilla” war with my sister

My sister has always been the jealous type of person. She likes to be the center of attention and to be the best at everything. She can’t stand it if someone is congratulating me. When we were teenagers, I won an award at school for perfect attendance. My grandmother was bringing me flowers because there was this whole ceremony thing and my sister literally pushed me down before my grandmother could get to me to hug me. She’s just crazy like that. So my boyfriend of four years and I recently got engaged. We went on this perfect vacation to celebrate our engagement. We get back and we’re talking to my parents about a possible wedding date. We have known for a little while now that we’d like to get married in June of 2019 and we said we liked June 22nd as that’s the only day the venue we want has an opening. My sister was present for this whole conversation but wasn’t really saying much. And this is where I get pissed off.

The following weekend, my mother tells me to log on to Facebook and see what my sister has posted. I login and see she has posted an engagement announcement. Her and her boyfriend of SIX WEEKS have decided to get married. And guess what date they are telling people to mark their calendars for? Yup. June 22nd 2019. I’m so flabbergasted. I am crushed. I don’t care that she’s getting married but did she really have to pick the date I wanted to use? And it’s not just a coincidence because who picks the date the day they get engaged? My boyfriend and I had picked our date out so soon because we’ve been talking about it for months. She hasn’t even known this guy for that long. Is it completely wrong for me to hope they don’t last? I know I sound selfish and bitter, but I am. This wedding is something I’ve dreamt about forever. And we will likely have to choose a different venue now. I wanted that specific venue because both mine and my fiancé’s parents happened to have gotten married there so it was special to us. But they have no openings on any other day in June.