Aitah for asking to be paid back?

This is so stupid, but I have the kind of family who likes to make me feel small and stupid all the time.

I (18f) have an older sister (19f) and she is very irresponsible when it comes to money. This year, I got 500€ from the state every month for school, and she has a job where she’s paid around 1000€ a month (depends on the hours she works).

Well, she’s always asking me for money, and usually she pays me back. But since February, she’s been saving up for a car, and she stopped. At first it was just like 80/100€, but it quickly went up to 500€, and I also paid for my driver’s license this year so I didn’t even get to start using my own money until April, when I was done.

The thing is, she always says she’ll pay me back (it’s still an entire month of money for me) but she never does because I’m always put at the bottom of the priorities for her. I’ve had twenty cents on my account for 2 weeks, and she got paid 1500€ last week, so I thought she would paid me back (especially considering I was literally scraping by) but she gave 300€ to her boyfriend, paid 200€ for clothes and shoes, and she says the rest is going to her savings for her car, so she’ll pay me back next month.

Her contract ends in July, and I won’t get paid until next week (I also stop getting paid in July). So I’ve been feeling like she’ll postpone again and again until it’s July, she has nothing left and says she’ll pay me in September.

My mom also told her to pay me back bits by bits so she doesn’t feel it, and it annoyed me because I’ve been feeling the lack of money for weeks but when it comes to me it’s not an issue suddenly?

So I got pissed and I told her I was sick of it, she called me an asshole and paid me back. But I feel like I am the asshole since my entire family has been giving me the stink eye.

I didn’t originally feel like I was selfish or annoying. I didn’t even start getting irritated until I saw how she did NOT want to pay me back even when I needed it. But then again she’s been saving up for a car, and it’ll make her life easier for work, so that’s why I feel like shit.

But if she really was saving up, she wouldn’t have given that much to her bf and wouldn’t have ordered so much clothes instead of paying me back when she knew I didn’t even have 1€ on my bank account.

So, aitah?