<human>: I'm sure this situation has come up before but it seems like everything I've read has to do with vacations planned for months after accepting a job offer...mine is just a week after I start. 

Interviewed on Tuesday, was offered the job on Wednesday, and I wasn't sure what to do so I rushed my decision and agreed to start next Tuesday. I panicked and never said anything about this vacation because a) I need the money, b) I wasn't sure when to say anything. Now I'm torn between "don't be an idiot, shut up" and wondering if I should call them and explain the situation? Or wait until I get there on Tuesday and sign paperwork? I don't have a ton of money invested in the trip, but it involves a specific event and multiple different people (including family). It's been planned for months now and would only require a few days. It would be upsetting to cancel, to put it mildly.

This is just a minimum wage, menial labor job so it's not like there are any "negotiations" and I doubt I have much leverage, even though it seems like they really want me. I know I can take unpaid time off before paid vacation benefits kick in, but I'm supposed to give at least 2 weeks notice and get it approved. My original plan was to ask about it when meeting with the manager Tuesday morning but now I'm scared it'll reflect poorly on me to even ask, or to wait so long.

Could you distill the essence of the text into 1-3 sentences?
<bot>: Vacation scheduled approximately one week after starting new job, haven't told them or asked about it when accepting offer, can/should I still say something?