Back to work!

I’m starting a new job at Olive Garden on Tuesday, and I EBF. I do pump, so I have a good stash. My concern is HOW THE HELL AM I GOING TO GET AWAY WITH pumping AT WORK... AT MY NEW JOB?! I’m going to be the newbie and I don’t think they’ll appreciate my “I need to take a 15-20 minute break to pump” on my first day! Will it mess with my milk supply if I don’t pump at work? I go in at 4 on Tuesday and will pump and breastfeed all day before I go in just to make sure.. any advice on this subject?