I really sympathise, I was terrified too (had a previous EMCS). Don’t listen to people spouting crap about CS - yes, it is major surgery but it’s routine surgery and as safe as any other op.
I was told not to shave as they prefer to do it themselves. They don’t shave very much, just over the area where the incision will be made.
I was worried about the nil by mouth too but it was actually fine. Mine was an afternoon section and I was told
no food after 0600 (so followed midwife advice and got up at 0530 for breakfast and omeprazole), no drinks after 1000, and arrive at 1100. I drank gallons until 1000, had a small drink at 1200 with more omeprazole - and I did rinse my mouth a couple of times without swallowing when it felt dry. It was actually fine - I think the adrenaline takes over.
I was due to go down at 1500, although we were actually summoned to theatre at 1400 - there was some hanging round, including while partner got into scrubs, and then the prep - he was born at 1520.
Afterwards, you want to minimise rubbing the scar area - as well as big knickers, I’ve spent most of the last few weeks in maternity leggings and yoga pants. I recommend taking something like that for going home from hospital, but also nighties for in hospital - you will have a catheter inserted prior to the op (after the spinal has taken effect so you’re numb) and it will be taken out either later that day or the following morning, all being well. You’ll wear a hospital gown for the op and immediately after but it’s worth having a nightie or two in case it’s in for longer than you expect.
Stock up on paracetamol and ibuprofen in advance as you’ll be advised to take these daily at first when you’re home, and I would also get some peppermint capsules in case of trapped wind, and arnica in case of bruising - the latter really helped me.
Last thing: you’ll probably have to give yourself anti-coagulant injections for the first ten days. Make sure they show you and your DH/DP how to do them in hospital before discharge as you may prefer someone else to do them for you!