It's extremely unlikely that a C-section would affect your future fertility. What it can do is cause complications in future pregnancies and births. Very rarely, an embryo can implant in a C-section scar, which is a type of ectopic pregnancy, is non viable and very dangerous if undiagnosed and left untreated. Slightly more commonly, scar tissue can cause problems with placenta insertion. The placenta can attach over the scar tissue, hindering the flow of nutrients to the baby, or the scar tissue can cause the placenta to attach in a less optimal place, increasing the risk of conditions such as placenta previa. If you want to try having a vaginal birth after a C-section (unlikely if you opted for a planned C-section due to personal preference first time round, but not impossible), it makes your subsequent labour a bit more risky, with the possibility of scar rupture. And if you have repeat C-sections, as @RebeccaCloud9 says, it becomes more difficult for the surgeon to successfully perform each time. So if you want more than two children (again, unlikely if you are 36 now but not impossible), it's best to avoid.
Now, for balance. I had an emergency C-section with my first baby after my labour stalled. I didn't get past 6cm dilated and my baby started to get tired. I found the anaesthetic quite unpleasant, got the shakes and was sick into a bedpan during the operation. Seeing my baby for the first time was amazing and emotional, and I had delayed cord clamping at my own request. My baby was then taken away to be weighed and cleaned and I didn't see him again until I was in recovery, which I was not expecting. It took about 40 minutes to finish the C-section after he was born, which I also wasn't expecting. (Hadn't really thought about it before.) Once they start, the baby is out in a couple of minutes, but stitching you up again takes much longer. (This is a good thing because doing a proper job takes time and shouldn't be rushed, but it felt interminable at the time.)
Afterwards, I was really not very mobile. I had my C-section just before midnight and didn't get out of bed until the following afternoon when a nurse came to remove my catheter and helped me get out of bed to walk to the toilet. You don't really appreciate how much you use your abs to sit and stand up until they've been sliced open and sewn back together again, and you can't. That was the worst part of the recovery for me. It took a good couple of weeks before I was able to sit and stand up without it being scary and painful. If you do end up having a C-section, take all the painkillers you are offered afterwards and make sure your partner understands that you can't move around easily and they need to do everything around the house and the majority of nappy changes etc.
After the first couple of weeks postpartum I felt much more normal again and by two months postpartum I was exercising again. My scar healed really well and is small and neat. And obviously I had no damage to the perineal area and minimal pelvic floor damage. (You should still do kegels even after a C-section birth though.) I also didn't get post birth piles, which I did after my VBAC and were far more painful than either labour or my stitches. (Eat loads of fibre, drink loads of water and don't ever strain on the toilet. Piles are no joke and prevention is better than cure.)
I find that being prepared for all eventualities and understanding how vaginal labour proceeds when everything goes smoothly, the different possibilities about what might happen if it doesn't, and what happens during a C-section, is really helpful for allaying fears about childbirth. Giving birth is a huge thing, however you end up doing it.
On sites like Mumsnet you can get some amazingly useful information that women might be reluctant to share with you in real life, but you also tend to get more women talking about having experienced birth trauma, because they may feel more comfortable discussing it here. Some women do have hugely traumatic experiences and those shouldn't be minimised. And no one can guarantee that nothing like that will happen to you. However, the chances are it won't happen to you.
It's far more likely that you will end up with an emergency C-section but a reasonable recovery than it is that you will suffer a horrific birth injury. And equally, there's a good chance that you will have a straightforward vaginal labour with maybe a few stitches afterwards, and be back to normal within a few weeks.
In your case I would read everything you can about all types of births, and try to be mentally and physically prepared to have a straightforward vaginal birth, whilst understanding what the range of outcomes might be if things don't go according to plan. This will help you to write a realistic birth plan, advocate for yourself during labour if need be, and feel less scared.