AITA for refusing to tell my sister I have a problem with her boyfriend?

I am an 11 year old girl. My sister is 19. I have been doing a lot of activities with my dad since I was 5 and I'm travelled alone with him a few times. I travelled alone for the first time when I was 5 years old and I have done it many times since. I am familiar with airports and don't get anxious.<br><br>My sister was going with her boyfriend to his parents house for Christmas. They are flying out on the 27th and she is going to stay with us from 22nd to 26th. My dad had plans to go camping with me for a week on the 23rd but when he found out about her trip he asked me if I wanted to cancel or go ahead and he said he could take her to the airport on the 27th.<br><br>I said I wanted to go camping but told him I didn't want to leave her alone at our house because I don't like her boyfriend. My dad asked me why and I told him that I saw him get really angry at my niece when she was 3 and knew he had a bad temper and I worried about that and I think I will worry about it more if my sister is alone at the house.<br><br>He asked me what I wanted him to do about it and I said I just didn't want him to tell her. He said ok and I forgot about it until my sister got here. Then my dad told her he was taking her to the airport but didn't mention that he was only doing it because I said I didn't like her boyfriend.<br><br>AITA?