My oldest just graduated from college. Just like childhood, if feels long while you are in it, when it's over it feels like it went fast.
But, now I have a young adult that is permanently attached to me in a close and wonderful way for the rest of my life. I wouldn't trade any extra hours of netflix or going out to eat for having my own people.
Have as many kids as you are willing/able to have. I had 5. First one is a shock. Second one means one kid per parent. Third is now a full family, but the oldest is so thrilled about a sibling now and there is play and joy in the house. 4th and 5th don't really add any extra work (mentally) other than you have a few extra years dealing with kids. And you need a minivan. (which I love anyway for many reasons) The older the kids get the more they take care of themselves, and eventually add more to the family than they need.
Now, when my two oldest visit, we have a defacto party and we have so much fun hanging out and playing, talking, laughing, cooking together, making plans...
I get this for the rest of my life now.
Best investment I have ever made.
Edit: We know a family that both parents were single kids (they said their childhoods were lonely) so they had 7 kids and then adopted 7 more (all siblings from a messed up home). They love it, their house is like a dorm. I couldn't do this, so I think its so much about your life experience.