When I got pregnant the second time, I was waiting for that stage to end before I would live my life. Exercise, activities with kids, travel, writing, house projects... Then after the Lizzie came and things were so complicated, I still found myself waiting until she was older, waiting to get out of tangle of doctor appointments.
Then I was planning to start life after both kids were in school, at least three years away! Enough!
Anything I want to do can be adapted to start now, incorporating the kids and whatever challenges we face in our plans.
Some dreams may be better suited for the future, but there will be no more blanket attitude of putting things off for later when it would presumably be easier or less busy.
There is no perfect time, but the best time could be now.