It's easier to relax and have fun with your children when you know you have the resources to care for them. Age also brings self-knowledge and control, and you are less likely to project your own longings onto your children to fulfill your needs. Older parents can still maintain their careers if they choose because they have the resources to afford good child care - something they might not have been able to do in their 20s. And of course, the maturity level of older parents is a definite asset. They are past feeling like kids who still need to be parented and can move right into a positive parenting role.
Older parents are more calm, confident, and able to go with the flow.
Babies can sense this. Delayed parenthood can be the best thing for both the parent and the child. References Monthly Vital Statistics Report. National Center for Health Statistics, Vol. Report of Final Natality Statistics.