Ok ladies I need to know if I'm in the wrong. Please no judging, I just need opinions. Sorry for it…

Ok ladies I need to know if I'm in the wrong. Please no judging, I just need opinions. Sorry for it being so long. So my daughter's first birthday is tomorrow and I was going to have her party yesterday but my dad asked if could please change it because he was going to be out of town. So I changed it to the 15th. Then my mother in law asked me if I could change it because she was going to be out of town for the 2 middle weeks in July. So I changed it to the 29th. (But she ended up going out of town really early and is back already. )That's my nephew's birthday so I texted my sister in law (who I can't stand but I'm civil because my hubby asked me to be) to make sure she wasn't going to have anything for him and to make sure it was ok I have my daughter's party that day. She said she didn't even know if she was going to do anything so I told her I was going to have my daughter's party that day. She read it but didn't answer so I assumed it was ok since she didn't say not to. This was like a month ago so I already planned and invited everyone including family from out of town so I can't change it. I found out that yesterday she was arguing with my hubby saying that she doesn't know why we are having the party on her son's bday and that they aren't gonna go to my daughter's party cuz she decided to take her son to do something. Do you think I'm wrong for having it on his bday? The only reason I changed it was for my mother in law and nephew and other sister in law to be able to go because they were all going be out of town and my sister in law knows that. This is why I don't care for his family or to be around them.