How old are you OP? She's 23, I was AN UTTER TWAT at that age, really, if I met myself today, I'd be unbearable, but I was young, all posters saying, 'She's an adult', must be congratulated on having their shit together at a young age, that doesn't seem to come with compassion though.
She's your sister, it took me a good 40 years to have a really good relationship with one of mine, but now it's brilliant, really brilliant, I can't think of anyone else in the world I'd rather spend time with.
But if you'd asked me 20 years ago? I'd have laughed in your face, we couldn't have been more different, complete opposites.
HOWEVER, 20 years ago she phoned me, I was young, single, working in the City, she was doing her MA and was pregnant, things weren't great in her relationship and she was at sea, distressed and didn't know where to go, I offered to drop EVERYTHING to get a flat with her and help her with her child even though at that stage in our relationship we'd sooner have spat at each-other than chatted.
Because that's what family do, especially siblings, you have to have each-other's back, you may need it yourself one day. You have a shared history, the same experiences, one day, you'll realise no-one understands you like they do.
And yes, your irritations are trivial, you sound like children fighting over space, squabbling siblings.
I'm guessing you'll get over it though.