AITA for giving my sister food from my fast despite her knowing about it?

I (16M) have a little food allergy that causes severe reactions if I eat certain foods. My family is pretty understanding so my sister (14F) and I have made a plan. When I'm going to be apart from her, she knows that I have a meal bucket with me and she's allowed to eat from it as long as she asks. This plan is especially important because we live in a country where healthcare is bad and getting help for allergic reactions can take a while.<br><br>One day we were going to a family event where we would be apart for several hours. I was packing and my sister asked if she could have one of my energy bars. I said no and told her that I had already eaten one and that this one was for my fast. She tried to say "but you don't need it, I do!" And I told her "no, I'm sorry."<br><br>She came to my parent's fiday dinner fuming and telling them that I was a monster for starving her when I gave her food without permission before. My parents asked me what happened and I explained that I had already told her no and that I'm starting my fast and I didn't think she had a severe allergy.<br><br>My sister said that it was different because she didn't know if I had eaten already, but she knew that I was planning to fast. She also said that my allergies aren't as severe as she thought and that I was being dramatic.<br><br>My parents asked me to prove it wasn't that mild and I had an allergic reaction to some almonds that my sister gave me without permission. It swelled my whole head and neck and I looked like a blue alien. My parents were horrified and are still talking about it.<br><br>My sister called me an asshole for scaring her with that story and said that I was an asshole for giving her food anyway.