Girls Night Out

Me and my friends never really go out that much because we are always so busy not everyone has time to sit down in there life and just talk to there friends.
We had a lot to catch up on so we sit and talk and lost track of time and it was the best night but we have a group chat where we meet up with our other friends there is 9 people in the chat and getting everyone together in one place at the sometime, is hard very hard so we when as a four because it easier and quick to organises but someone in the group found out we where out and go angry that she wasn't invited because it was four friend that where very close in high school and we want sometime together.
I get why she got angry but is it bad that we wanted sometime together to get a word in edge ways and just have a night to talk and you don't have to drink ( every time we all go out we all end up drinking)  but have a meal we are adults not still in high school we can't have argument over someone not being invited somewhere like you are 20 grow up i know it's bad to say we are still friend but you know it bad say this about your friend but at the end of the day your can't keep playing high school games.