Do you think I responded okay to my sister? is she in the wrong?

Just a little background:
My sister and I have never got along but we were starting to get closer the last six months..until I got pregnant. I am the younger sister but I got married first & have always acted more mature than her. My husband and I tried for TWO YEARS to conceive and thought we couldn't get pregnant before we found out about our baby! Through this time my husband and I have talked about names & the name we chose has been a contender for the last two years! 
My sister helped plan our gender reveal party. Then the day before the party my husband and I, my sister and her husband, and our mom and dad were having dinner. When she found out we found out the gender she threw a fit. A literal fit. She said things like "I can't believe this! What's the point of having a party anyway? Ugh! I'm just so sad." Rude, yet understandable, I suppose, since she was planning the party... I'm used to my sister overreacting about things. But my husband was annoyed that she had started throwing this tantrum about something she has no say in and says, "This is OUR baby. We found out bc it was OUR decision. Don't make this about you." 
Later that night, THE DAY BEFORE THE PARTY, she did tell me a few names she liked but I legitately don't remember her ever saying she liked the name we had ALREADY picked. And even if she mentioned it, I couldn't say anything bc she didn't know if it was a boy or girl. 
Then we announce the name after the reveal. Several days later I get this text exchange:
I haven't responded. My sister has a history of bullying me. She is very much a bully. But seriously to reiterate I have been keeping a list of names since my husband and I were TTC for the last TWO years. I have told many people the names I like. I have mentioned Ellie before. She feels played?? I should've pulled her aside when I didn't even remember her saying that name??
So what do you think? Is it ridiculous she has started this??