My husband is a bit older than you (mid-50's) but we are young at heart and have young kids. His was Gleason 3+4, diagnosed late last year, and he had his robotic prostatectomy with nerve sparing and lymph node removal on Jan 22nd (8 days ago) Today he had his catheter removed and the pathology was clear, so we are feeling good! I cannot emphasize enough that you should do your pelvic floor/kegel exercises before the op and after the catheter is removed.
Do get a bucket to keep your overnight bag in- keeps it off the floor and contains leaks (we had no leaks, though, but it did keep the dog away from the bag, lol!)
Definitely find a pair of loose tracksuit bottoms or trousers a size too big. My husbands waist is a 36 but was 40 right after surgery and is a 38 at the moment so fastening trousers is awkward and hurts those wounds. Loose pants are also important as skinny jeans won't fit a catheter bag inside them after all it's only for a week or so, start a new trend ;-)
You may need help getting in and out of the chair as your tummy will be really sore so identify a good arm chair in front of the tv/computer, wherever you like.
Similarly getting on and off the bed can be very uncomfortable for first few days. Take it slowly and try and roll on your side and push yourself up (or have someone pull you up, just try not to use your abs.
The catheter may bother the end of your willy. Get some instillagel to ease this. Also keep that area clean and wash gently with warm water.
The leg bag is OK so long as you get it positioned to suit you. Even though my husband is 6foot3 we trimmed the tubing from the catheter to the leg bag so it was more comfy for him. He also wore a "garter" (old bit of elastic) round his thigh as well as the catheter grip to keep the tube from moving around.
If you can, walk asap. He was up within 3-4 hours of surgery walking with a nurse round the halls of the hospital and they did that overnight with him too (while I was at home tucked up in bed!)
Keep up with the fybogel for a couple of weeks (pre and post op) as it makes it much easier to go for a number 2.
Get a small whiteboard/ notepad and write down the type of meds and the times/days you need to take them and you can tick off when you take them. My husband had pain meds, one pill once a day, another twice a day, another for 5 days only, another alternate days, etc etc. This should reduce after a week or so but you need to keep track!
Keep your pills in a biscuit tin or Tupperware type box or toiletry bag so that they are all together and out of the reach of kids and pets. We also had a tray on the bedside table with wipes, tissues, catheter bits and bobs. That's all gone now and it was untidy for a while but necessary.
Take a pair of incontinence briefs to your catheter removal appointment and a pad or two to put in front, then if you have a leak on the journey, you just remove the pad rather than having to get completely undressed in a public loo! Once we got home my husband took off the big pants and put on regular undies (not boxers) with a couple of pads inside. Fortunately he has felt the urge to wee and has not yet had a leak but who knows what tonight/tomorrow might bring?
I would put a pad (like the puppy training pads) on the bed in case of dribbles when you change from night bag to day bag. There was no room in our loo for the 2 of us so we did all that in the bedroom(!) I believe they are good for after catheter removal too as you regain control of continence.
As you are young I am sure you will have few side effects and will be back at full health within a year. I really wish you well and look forward to hearing how you get on. All the very best from the polar vortex!