Is AUTHOR wrong in the post ? POST : A little back story. 

My 21st birthday is this Friday. I was planning on not working because I had requested it off and would be going to the Secretary of State to renew my license and tags. 

Well last week my boss asked who would be covering my shift(7am-3:30pm) for me on my birthday. I said I didn’t know because they had already approved my time off for Friday. My sister happens to work where I work and we both work in the kitchen. My sister overheard the conversation and told my boss that’d she’d be able to cover my shift, the only thing was she had an appointment that morning she would have to leave for then come back later. My boss said that was okay. 

Fast forward to yesterday, saw my sister at work again. Reminded her about Friday and she said “I don’t work Fridays”. I’m confused at this point and recite what she had told me and my boss last week. She then said she never said any of that and that she wouldn’t be working. I’ve exhausted all my other options of coverage. No one can cover me. I feel like I’m going crazy because my boss also clearly remembers her saying she’d cover for me. 

AITA for being upset with her?

I don’t mind working on my birthday but it just bums me out since I had already asked for this day off three months in advance. 