Never again....

I let my younger sister take my car to school today since I didn't have anything to do in the morning and told her she needed to bring it back at lunch (around 12:15) so I could do the things I needed to do in the afternoon. But instead of bringing it back she decided to drive 15 minutes away from her school to get lunch and then bring it back. It's been almost an hour since her lunch started and she still isn't back with my car. Am I right to be frustrated about this?

I honestly don't think I'm letting her use my car again...