Me and my sister are both pregnant!

I got a phone call from my sister that she's 12 weeks pregnant. I was so excited for her because she's older than me but I got married first. Hubby and I were planning to tell my parents next weekend that we are 8 weeks pregnant but I feel like I'm going to "rain on her parade" if i share the news that I'm due one month after her. Do you think I should wait for the excitement about my sister to die down before I tell them? My husband says we should tell them because it's doesn't always have to be about her (she likes attention and feels the need to complain about everything) but I can't tell at this point if my parents will be happy for me or not because my sister will rely on them for everything now... Any thoughts or advice would be helpful! Thanks.