Kicked out of the bridal party for getting married

I need some advice so I don't handle this situation poorly. My cousin and I were both engaged around the same time (over the holidays). We both asked each other to be in our bridal parties. Because she was engaged first, I asked her if she had chosen her date yet because I knew we were looking at the same time. I told her FH and I really wanted to get married in March on our three year anniversary, but I wanted to see if she had already booked that date. She told me she had chosen April already and didn't think it was appropriate for me to get married so close to her (5 weeks apart). She thought I was doing all of this on purpose to beat her to the punch. She was pretty hurtful, so I backed off initially, but my MOH convinced me I wasn't doing anything wrong and should pick a date that works for us. So I picked the date and explained my reasoning to my cuz and told her how excited I was for both weddings. She told me she is kicking me and my sister out of her bridal party. She told me I can explain to my sister that I have ruined her chance to be a bridesmaid with my disrespectful choices. I am baffled and unsure of what to do. It's been a week now and she is still not speaking to me and her family isn't speaking to mine. Did I do something wrong? What do I do to make it right?