It’s definitely more about where you’re at in life than your specific age I think!
I’m pregnant with my first at 31 and will have given birth while still 31 if all continues to go well (I’m fifteen weeks).
For me, I realised around 27/28I wanted a baby and soon, but was with my ex who didn’t. So we split and I dated specifically for men who also wanted families relatively soon. Met my OH at 28, he was 24, was surprised he also wanted kids within a few years. Now I’m 31, he’s 27, will both be those ages when baby arrives.
For me it was important to be in a solid relationship of a few years with someone who wanted a child as much as I do, to be earning what I consider a decent salary (when we started trying our household income was around £70k I think), to both be well into our careers (I’m as far as I can realistically get professionally and in terms of salary so I’m not concerned about my career stalling now as I’ve reached the highest peak I can envisage for a long time, we’re both qualified professionals), to have savings, and to have either purchased property or been well on the way to doing so. We started trying once we had enough in the bank to buy a house and got pregnant during the mortgage process and will be moving in five months before the baby is due.
It’s the perfect time of life for us due to the stability we have both in our relationships and professional lives/finances. I’d have happily done it late twenties if I’d achieved everything I have now but I hadn’t.
Wouldn’t have wanted to wait later than 31 due to endometriosis/blocked tube and subfertility but if I hadn’t had met the above goals I would have done. I’d rather wait and bring a child into the best environment I can provide than rush it and struggle. It’s so lovely waiting for this baby while knowing we’ve removed a lot of the pressure that comes from being skint and in insecure housing (been there, on both counts!).
We’d have liked to have been married first but didn’t want to delay TTC as fertility is finite and we can marry anytime. I did look into the legal aspects and as I have my own career/income/savings/both jointly own the house I don’t feel at risk having a child with him unmarried, though I’ll be making it a properly to get married before baby is one or two at the latest.