AIO about my sister planning her wedding a month before mine?

My Fiancée (20M) and I (20F) have been engaged since June of this year and we've been planning our wedding to be in April. We don't have the exact date set- but we've been telling everyone the middle/end of April. My Fiancée and I are catholic and so we have to go through some classes before we can get to literal date set. My sister (25F) has known all this information and is going to be my maid of honor. She just got engaged to her boyfriend (23M) a week ago and she just texted me the other day saying that her wedding has been set for March. And I love my sister dearly and I'm soo happy for her, but I'm slightly upset that she set the wedding for the month before mine... I should also note, she's mentioned a couple times to me since I've gotten engaged that she's kind of upset with me for getting engaged first. I wouldn't have minded if she talked to me first about the date. But she's already got it set, and I feel like she set it to March because she just wanted to get married first... They also don't have much in terms of money so I'm genuinely concerned on how they're going to afford a wedding that soon... I genuinely feel like they're rushing just so they're married first. I have not said anything to her about me being upset, because I don't want to ruin her special moment. I just feel like I have been walking on eggshells about my own engagement to not upset her, and not she's set her wedding a month before mine. Am I overreacting?