Is AUTHOR wrong in the post ? POST : Throwaway because my cousin knows my reddit. 

My cousin and I are close; she's a few years older than I and we live in the same city and have similar hobbies. 

My bf (who she is also close with) and I invited her to a concert tomorrow for a band we all LOVE about four or five months ago. 

My cousin is known for being non-committal with plans and is also known for not answering her phone (texts and calls) very often. 

This is always something I've known but in recent months it's become more annoying. She asked me to catsit for her but did not reply to my texts asking about details until the day she needed me. She has flaked out on concerts last minute before and it is never known for sure if she is coming to a family event until she is actually there. 

Since she is family and we are genuinely friends, I put a lot of effort into coordinating our plans. I text her mutliple times, I call, I figure out as much as I can about a plan and relay the information to her, I make it as simple as possible so that she can just show up to the thing and not have to worry about coordinating anything. 

This usually works out, maybe 60-70% of the time she shows up. I wanted to ask WIBTA if I did not do that this time? We have known about this concert for MONTHS and I texted her at 11:00am this morning asking if she bought her ticket/if she wants to do dinner together before we go and she has yet to reply and it is 6:00pm now. WIBTA if I didn't text her anymore about these plans and leave it up to her to plan with me/show up tomorrow? It's fine if she doesn't want to go, I just wish she'd tell me so I can stop wondering.  

I know this kind of sounds like a validation post but she has an affinity for not realizing her mistakes. I also do not know if she really knows any better, I don't think she realizes how rude it is to just not reply. 

So, WIBTA if I didn't text her/follow up anymore? 