Aitah for apparently leaving out my cousin on vacation

Me and my cousin were both 14 year old females and we went on vacation with 23 members of our family Total. Me and this cousin let's call her lilly have been very close for our entire life but there has been many arguments and silent resentment going on but for about a year we've been fine. So we hang out all the time for the one month she comes back in town yearly. The week leading up to the vacation she was really moody and just rude in general so I warned my other cousins before they got there that she was being really grumpy but once we got to the cabin she seemed fine. Anyways the other cousins do not like her very much because she constantly is the victim of everything and a lot of the narrative they have of her I have contributed to by complaining. I would like to point out this isn't trying to get them to dislike her this is how I see it telling my side lilly has also told our grandparent her parents and aunts and uncles about our arguments were she paints herself as victim and lies about some stuff causing them to dislike me. Lilly on this trip often sat on the couch in our lodge that everyone was staying at reading a book. This is completely fine in my eyes and I also enjoy a good book. Anyways all of us even with some not liking her make an effort to invite her. On the first night when we went out to do a grocery run for my other cousin to make deserts I asked three times if she wanted to come because she hadn't hung out the whole day with us. She said no and read her book. We did hang out a couple times throughout the week playing pickle ball but other than that she didnt ever make an effort to invite us to do things or ask to play the board games that the rest of us liked playing. We also invited her to play stuff with us like the game "the mind" were every couple times we would ask do you want to join and she would say no and read her book. I was taking extra care at the beginning of the trip to invite her because she and I called before the trip and she said she was a bit nervous of being left out so I wanted to make sure that didnt happen because I've felt that before and I don't want anyone else to feel that way. So over the days we ask her less and less to join because she keeps turning us down. Then one day two of the housholds in our family we stayed with decided to go on a long hikeing trail and it was just going to be them but if anyone wanted to join they could. Me and Lilly were not included in either household but I really wanted to go on this trail so I asked my cousin anna if I could tag along and they said of course so I joined Lilly heard this because she was in the same room so she completely knew she did not join she went upstairs and read on the couch. Then we left after everyone coming met in the living room right next to the couch lilly was sitting on. Then while we are gone annas mom overhears Lillys mom and my and Lilly grandma talking about how Lilly is super shy and everybody leaves her out by not asking if she wants to join. Anna's mom then when we get back form hiking tells us this and even annas dad is like thats not our fault why are they getting blamed. And we talk about how we have invited her to hang out and she rejected us. Later my uncle goes to my brother who is just chilling upstairs on his switch and says to my brother 20m who he is on very good terms with "as a father and an uncle I am very concerned as to why Lilly is constantly left out" to wich my brother told him she's not and we've invited her. My uncle didnt like this very much. Later that day we were out getting ice cream and we have 22 people so we took 3 benches up and me and anna were sitting at one bench and were like let's move to the kid bench wich had all the other cousins and we asked lilly who was at our table if she wanted to join us over there and she didnt respond all she did was look at her mom with a what is wrong with them look. Fast forward we are at the lodge and I get dirty looks from lillys mom the whole day her mom does thank anna for inviting lilly to sit with us.That's the end of the story please respond with answers and if you have any questions I just want to know to hear from objective people because sometimes I'm worried I'm actually just super self centered and so I can't see it's my fault.