I think it is very different to have your FIRST child at 50, versus someone who is 50 with teenagers thinking of starting again by having a baby.
I had twins at 47. I'm now 51 with active 4-year olds, and work full time in a senior, stressful role.
I started TTC at about 40, and after 10 IVFs, 2 miscarriages, I finally had my miracles. :) Yes, I'm tired, with very little time for me, but I think I'd be tired if I were 30 too! I spent my 30s travelling, building up my career, loads of hobbies, etc, so now I am happy to just focus on the twins and work.
I'm not worried about age. My parents are healthy 93/94 year olds. They were in their 40s having me and my younger brother (and older siblings too). Hopefully I've inherited their long-life genes. I think having kids later in life keeps you young-at-heart. e.g. I go ice-skating regularly with the twins, and will take them skiing starting next winter. I'm also senior in work, so have the flexibility to manage my own schedule, and do 90% of drop offs/pick-ups and can attend all school events.
I also was proud to have an older mum when I was a teenager. Back in the 60s/70s, she had to give up work when she got married, so most of her friends got married relatively later (in their late 30s) so they could have some career before having to give it up. So the children of my mum's friends were around my age too.
The only downside, is that I probably will not have a huge amount of time with any grandchildren.