I recently quit my first ever job. I hadn’t worked there long, and it was just as a table clearer in a small cafe. I mentioned in the interview when I was applying that I’d need my exam results day off and that that was a dealbreaker for me as those exams are probably some of the most important ones that I’ll ever do.
In the interview my manager was fine with it, but a fortnight later when I was finally getting those confirmed she turned around and told me I couldn’t have it despite there clearly being enough staff to cover my absence and even when I got someone who would be willing to cover me. So when a few days later I received an all round better job offer I quit with a few days notice.
I know it would seem like throwing a tantrum, and I get that it may be busy, but I made it very clear that unless I got this holiday, I wouldn’t be taking the job.