It seems like, to me, somewhere between 30 and 35 is a really, really good time to turn your eggs into babies.
I do think taking the 20s to take the most chances you can is important, because you're not going to hurt anyone else during that time. And if you do have a partner, you need a couple years to rehearse that relationship.
Eventually, all mentor-disciple relationships are meant to pull apart, usually sometime in the mid-30s. Those who hang on, eventually the mentor drops the disciple, and that's no fun.