I think its just a case of when it 'feels' about right and you can almost afford them.
As Ive basically used up 3 decades and am no closer to a stable relationship let alone children this is a mute point for me right now. However, my simple guideline is to be with someone I love deeply and plan to stay with, and for my partner to want them as well.
I'd always wanted to have children young (ie age gap and health) but as I get older I have less choice in this, BUT I will never choose to be a parent outside a relationship to satisfy a biological urge/clock. So for me, physically (or emotionally?), any time from now if the opportunity presents itself, however if it never does then I'm pretty comfortable with that as well. I feel no society of family pressure to have them and think its a question for the relationship (again if that presents itself).
But if Im going to have an opion (as we all do
) on what I'd do in SueC's situation, I'd have a health check, get the new kitchen and wait two more years
.