Really annoyed with sister- always late!

[1reason]

AIBU?

I meet up regularly with my DS. Unfortunately, she is never on time..always late.
Today, I suggested meeting at 1pm in a cafe..she turned up 15 minutes late with no explanation or apology. Even if I ask her to choose a time then she will still be late!
It feels as if she treats me as if my time is not important. It's OK for me to have to hang about / sit and wait for her to turn up.
Feel like stopping seeing her. Would this be reasonable? Just can't understand she makes no effort to be on time ever.

Have you brought this up with her?

I would tell her a different time and then turn up at the same time as her or I would tell her 1pm and arrive at 1.30pm with no explanation or apology see how she likes it. Sometimes that’s the only way people learn

I don’t think 15 minutes is terrible. Is it ever more?

Also asking if you’ve ever brought with her?

Some people are time blind. Also some people don’t care if they’re waiting. If it’s important for some reason that she’s on time then ask her to make an effort to be there before the start time, if it doesn’t matter ask her to keep you updated or share your location so you don’t rush or you can pop to other shops while you wait.
the only thing that really works is just cancelling meeting but I wouldn’t do this over 15 mins

Ps the ‘she thinks my time isn’t important’ isn’t true as late people aren’t late on purpose. Just like messy people aren’t. ‘She thinks I deserve to live in a cess pit’ no she doesn’t she just doesn’t notice or get bothered by mess like you do, is the equivalent.
If you’re going to criticize her make sure you accept what you may have coming back to you.
eg she might say ‘it’s reallly hurtful you think I don’t value your time when I used hours of my time baking your bday cake and helping you move, you’ve never done anything like that for me in fact you never send me a bday gift’ etc

I think you’re within your rights to be annoyed about the repeated lateness, but I think it’s a bit extreme to jump immediately to “stop seeing her”. Have you even tried to talk to her about it? “DS, it really upsets me that you’re always late as I find it embarrassing to be sat on my own like a lemon and it feels like you don’t think my time is important…”
How she responds to the conversation and what action (if any) she takes to change her behaviour should then be the indicator of whether you continue meeting up with her or not.

I don’t think 15 minutes is terrible. Is it ever more?

Depends how long the meeting is for. If you've got all afternoon to hang out, you might not be too bothered about 15 min, but if OP only has an hour or so before she has to go and pick up a child from an activity, for example, then it's quite a big chunk of time.

And if someone is late every time, then it's annoying.