Concur with all BL has to say above. Your SOH will be tested, and there will be people around you who struggle to understand the old saying:
"If you can't take a joke, you shouldn't have joined"
I was lucky, as I'd been at boarding school for ten years beforehand, but many people who've lived at home, been looked after by mum, and pretty much lived their life as they wanted to, do struggle to get around the idea of being on the go for 18 hours 7/7, sharing a room with 3+ others, and being totally shagged for weeks.