sister and baby shower drama - rant

I'm 27, my sister is 29. We have never been close due to the fact that my sister has always talked down to me, never treats me with respect, and is very petty and holds grudges and gets mad over nothing. She is extremely terrible at communicating and has been this way her whole life. To start we will go months and have gone years without talking. She has admitted me to once when she was in therapy that she always talked down to me cus she was jealous I was younger and more successful. I bought my house, car, and got married before her all with no help from my parents. I was more accomplished in sports, academics, and popular in high school. And now I've been traveling internationally and received my MBA. So she's always just said things that were rude and I would just block her because it's so draining trying to have a relationship with her. This year she decided to have a destination wedding... $2500 for 3 days for 2 ppl in Mexico. My hubby and I purchased the tix and we ended up cancelling because we have been TTC for over a year and 2 weeks before the event the CDC announced the Zika virus could stay in semen for 6 months. So we've gone through a MC before and financially and emotionally did not want to the risk. Also she had a large wedding at home just the month before. My father nor the grooms sister was going to the destination wedding. So we found out we were blessed w our first child in July. And then I heard from my mom that my sister was also pregnant. I'm due 3/17/17 and her 3/7/17. We have announced and everyone knows but she nor her husband has congratulated us. They have not announced and are keeping it a secret (maybe cuz of Zika). Anyways I am a super planner and my friends and I already booked a baby shower date and ordered invites for 1/29/17. Today my mom texts me and say ur sisters shower is that day too. I'm so annoyed because I've told my mom and older sister about my date 2 weeks in advance. My pregnant sister is not a planner and I highly doubt she has a real date but is doing this to be petty. She is known to be last minute with everything.  I'm so tired of her.