This is 100% your fault. If you knew you were in the works for a promotion, you know you shouldn't ask for time off, especially when it's something you don't even want to do. Be an adult for goodness sake and put your foot down.

The way I see it: OP is 17 and has been at this job for a year and boss has an opening in a position OP could transition to. It is probably a crappy restaurant/fast food/retail job where schedules suck and time off is hard to get. OP's parents spring this lovely family vacation on her saying she has to go because they already paid and they aren't going to leave a teenager by herself for a week or however long. The last minute request of several days off is hard for the boss to reschedule and makes her angry. The boss broods on this and justifies the action of taking away the promotion by thinking OP is irresponsible for doing this and doesn't put her job first. This is what makes the most sense to me given the parameters, so I don't think it's OP's fault or that she could've done anything.

This happened to me also! I organised 2 months out to have one day for my birthday off and about 3 weeks out, my boss offered me a contract to start in 2 weeks. I signed and a week later she told me that it 'wouldn't look good' having a day off so soon into the contract.

Why did you not want to go on the vacation? That sounds quite odd.

Wow, YDI for not being appreciative. Many people would kill for a vacation and you can only find fault in it. You have your whole life to work so enjoy the little things and days off when you can.

Time to find a new job.