My 3rd is due in July, and I'm 30. Had our first when I was 23. I'd personally much prefer to be young when I had my kids. But that's personal preference.
More important is the age of the women. For women past 30 it starts getting harder to conceive (and gets harder every year after). Especially if they've been on the Pill for a long time.
There's also higher risks as you go past 30, cesareans are twice as likely for women in their 30's compared to those in their 20's. And the miscarriage rate increases past 30 as well.
Past 35 is even worse, chances of high blood pressure double, also the chance of having twins shoots up after you pass 35. And miscarrage rates are about double that of someone at age 30.
After age 40 it's very very hard to conceive full stop.