AITA for wearing down my sister's car??

I (22F), my older sister (32F) and my mom(64F) are bickering over cars. (on my main account because no one in my family knows how to use reddit! Teehee!)

Last night my mom was on her way to pick me up from my work (I work on the other side of town from 4pm-2am,about 30mins away) and the car (a Ford escape) we all have been using to commute to both of our works, had suddenly started bellowing smoke, burning up, and causing some type of fluid to go everywhere. Lucky my mom is a very good driver and made it to a gas station safely(thank God). This morning we took it to a mechanic and they said that one of the belts in the car was so severely worn down that it broke, and caused the radiator to crack (hense the fluid) and that it would be a easy fix (yay!). And my sister is blaming me for the belt being so worn down in the first place because of me commuting to my job( that I only have been at for about a month). She said that me and my mom need to find another because this caused her to stress out about moving and the health of her car in the future so she's giving us 3 weeks.

For context: - when we first got the car a few years back, I was in college and was getting a good amount of FASFA, so I had 2k saved up to help my sister buy this car (she also pitched 2k) and bought it from a nice elderly couple. -my dear sister that I love deeply, is terrible at taking care of cars. She has no knowledge on how to properly check oils, or fluids or keep track of when to get it checked out again. Me and my mom have told her plenty of times to get it checked and she "was busy and forgot" most of the time. -SHE KNEW ABOUT THE WORN DOWN BELT!!! the belt issue has happened before, and the mechanic had told her that she needed to replace BOTH belts. In which she only replaced one of them at the time (this was last year) due to "financial hardship" -Im also footing the bill FOR NOW, my sister doesn't get paid till next week so I'm helping her pay for the cars maintenance. BUT she is planing on paying me back when she does get payed.

So, I call upon you dear Redditers to bless or smite me with thy judgement!