my close friend didn’t invite me to her party

ok so i’m 16F and my friend who is turning 17 is my close friend, we’ve been friends since year 6 and have been in the same friend group like forever. being honest, we’re close but not best friends, but like we always hang out in groups and like basically she is a close friend. Or at least that’s what i thought until she decided not to invite me and this other girl in our friend group to her birthday party. We’ve always invited each other to our parties and i’m just wondering why now? nothing has happened between us…. this other friend who ill call meg was also not invited. But see like it’s not petty kind of “oh she didn’t invite us” and it’s not going to the party that’s bothering me. It’s just that’s weird because we’re in the same friend group. It’s us four, so me, meg, i’ll call the girl who isn’t inviting us Ruby, and this other girl i’ll call mia in the friend group. She invited mia, excluded me and meg, and invited 5 other girls. But the thing that really gets me wound up is three of those five girls aren’t even that close to her. They’re like “popular” girls, although popularity isn’t really a big deal at our school, but objectively they are like yknow. The way i know this is because one of the girls who was invited, who’s a good friend of mine told me and was confused as to why me and meg weren’t invited. So yeah, i’m just really confused and to be honest upset she decided like our friendship from year 6 doesn’t really matter. I know birthday parties aren’t end all be all, but I just feel it is sending a message. I don’t want this to like affect me, and to be really honest this friendship isn’t one i’m holding in high regards anymore (long story short i tried opening up about my life once when she ASKED me about it and she kind of threw away the subject but yeah). But yeah this is a bit of a rant i guess but im open to advice i suppose. I don’t think im going to talk to her about it though, because going into year 11 i kind of can’t be bothered to deal with stuff like that…she can be aggressive when she doesn’t get her way so actually thinking about it i dont mind not being friends with her. idk lol