Who’s in the wrong?

So my 18 year old sister doesn’t have her own car. I needed my car because I was going to go out at a specific time (I told her not to take it). I went downstairs to get my keys and it was gone, so was my car. She said she’s going to see her friends and that she’s so late. So I had to wait for a whole hour for an Uber to pick me up when I was planning to go earlier. This pissed me off so much she said that I don’t care about her and that I’m a horrible sister because I told her not to take my car. I feel guilty and a very at the same time. What should I do?