Putting aside any idea of offence, I get where you are coming from OP you feel it was was old for you and it is not a personal offence to anyone else. I never had ds until I was 35 and although it is not uncommon, even more common in modern times, it doesn't change many biological facts.
There are lots of reasons I regret being an "older mum". Regrets personal to me and my circumstances and while I think about them sometimes I don't dwell on them.
dc2 never happened and time ran out on the oldest we were willing to keep TTC.
My ds had a brilliant relationship with his grandpa, but then had to watch his health deteriorate as he struggled to breathe with COPD and then lose him at just 10 years old (because I was also born when my parents were "older", as I was their 4th dc). My dad would have been a brilliant role model for him through his teen years.
His exam/teen years coincided with menopause, my mum being elderly/ill and needing a lot of support. And dealing with that, raising a teen, supporting exams, together with FT work was a tough few years. And I lost a lot of my own identity during those years and still trying to find it again now.
I am aware, if ds follows the same timescales, I am unlikely to be a grandparent until I am in my late 60s/early 70s and like my dad I possibly/probably will not see that grandchild grow to adulthood. I have friends/family around the same age as me who have dgc ranging from babies to teenagers and I am jealous that is still at least 10-15 years away for me. I am making do for now spoiling my beautiful great-niece.
Conversely, because we were financially secure and secure in our relationship by the time we had ds we have lasted the distance, we have been able to do significant things for ds we might have struggled with if we had him earlier and not had the same career/job progression. He was raised by mature, steady and calm parents that loved every part of parenting, even the hard parts, and that also helped to mould him into the lovely young man he is today.
You have no idea how life would have turned out if you had your dc younger. You will have had different regrets, everyone has them! Take what you have as it doesn't sound too bad, count your blessings, put your regrets aside, and simply enjoy your old age 🤣 parenthood.