ETA: I think any time to have children is probably the worst possible time, except for all the others.
This.
DD is now 8, and is going to be an only. Both of us wanted 2-3 kids pre-DD, but were pretty sure she was going to be an only by the time she was in preschool. (DD was the easiest baby in the world, as long as you Never Put Her Down. She also has a cousin who is much higher-maintenance. We were really worried that DD would be the easy kid.)
Also, we all feel she would have been a great younger sibling, and a 6-year age gap would have been about perfect. But she actively disenjoys younger kids, has always been opposed to having a younger sibling, and plans to not have children when she's grown.
