Well, it is amazing what you talk about once you've had the baby too...
I would say that I know very few first time mums who didn't need some sort of stitching. I am not an expert and don't have stats, but I wouldn't be surprised if 50% is the overall number, with a much higher figure amongst first timers. I only know a few people who didn't need stitches first time.
But the reality was that it wasn't that bad. I've had both - episiotomy for forceps first time and a tear second. Both were stitched fine and both healed fine. I didn't have problems sitting down or anything like that. I have had some minor pelvic floor issues (I have to cross my legs if I sneeze!) but those were probably related to the forceps and it is something I am working on, not something that impacts my day to day life.
On the pool, part of the problem was that, in the area I was in at the time, the only option was a CLU. They don't really have the mentality that a MLU have. My ideal scenario for a first would be a MLU on site with a CLU for an easy transfer if you needed more pain relief. Also bear in mind that, if you get in the pool, there is no law that says you can't say you want to get out and have an epidural!
I won't lie, my first labour was a bit shitty, but mostly because of the horrid locum midwife. The forceps, the episiotomy, the stitches, they were all fine. The registrar was lovely. It's funny, before my first I was worried about all the same things you were, but in the end all those bits were fine- what made it difficult for me was how long it was and the sleep deprivation.