As Herbaceous has said there are plenty of older folks on this board, I'm nearly 57 and one thing I can categorically say is I have never, ever, not ever, not for one nanosecond, felt a 'baby pang' or even questioned how I feel or what I want. Not once!!
One of the great things about being 57 is that I don't have to worry about fertility anymore, my ovaries are dried up husks, just the way I like them!
I was born knowing I didn't want kids and nothing has ever dented my resolve in the slightest. As has been said, it's bollocks spewed out by the 'misery loves company' brigade who just want to drag you down to their level.
Funnily enough I know more than a few couples of my age group who couldn't have kids, typically they've said 'we were sad about it at the time, but lawdy are we glad we couldn't have kids now'....Also you'll find it's not uncommon for older parents to respond with 'good for you, if I my time again I wouldn't have kids either...'
I've found there's two groups of people who nag you about kids; parents with young kids (before they've experienced the teenage years) and lonely older parents. Both of which are undergoing their own emotional and hormonal issues and therefore can't be trusted with giving an objective view.
But in short, your hormones won't betray you and there's no internal battle to be fought....The only battle will be trying to hold your temper and not telling people to fuck right off and keep their noses out of your uterus.