I was 35 when I fell pregnant with my 2nd DD. I didn't feel old then, I don't feel old 7 years later, and I'm not planning on being "too old" for anything for, well, several more decades. LOL However, we are very happy having 2 gorgeous kids so that's what being "done" is about for me.
FWIW - there are more mums around who are my age-ish now than when I had my first DD @ 27. Some of them are onto a 2nd batch of kids (ie with older kids from a different relationship), and I think that's evidence that you can't ever predict how life is going to turn out in 5,10, 15 years from now. And the stats say that the younger you are when you start having kids, the more kids you tend to have before you're done. So I really don't think there's any kind of magic line in the hourglass sand.
I always planned to be done by 40. My plan when I was younger was to have two children, when I was 38 and 40. My mother and two of my aunties had babies at 40 and it always seemed perfectly fine and not "old" to me.
Turned out I was clucky and didn't want to wait that long. I still really didn't want children in my 20s and I'm so glad we didn't have them early and we travelled a LOT as I really draw on those life experiences with my partner before we had children and the strong bond we created over those years. But we decided to have our first baby when I was 32 and we'll be having our last just before I turn 38. I'm happy to stop a couple of years shy of 40 and I do feel done... but a little part of me thinks "well, two more years till 40... I could squeeze ONE last baby in..." lol
Bookmarks