Why do I have so much hate for my little sister

It’s not like I don’t love her I do don’t get me wrong I just have a lot of rude feelings about her. My sister is 5 years younger than me and I don’t know why but I genuinely can’t stand her she tries to talk to me but I’m ungodly rude to her I try to be nice and she does things to set me off… I don’t know why I’m like this I need to be a better big sister but it’s hard. I need a solid explanation maybe I am just a bitch but it’s so hard to be nice to her because everything she does triggers me..