I was a lot like this. I didn't end up having my child until I was 40, after something somewhat resembling an overextended adolescence. I think it was feeling I'd found just the right partner.
In any case, I knew I wanted children but didn't feel ready, then I did feel this could work when I was with someone I felt I could raise children with for the next couple of decades. And so far it's going pretty well.
(And then the teenagers landed on our doorstep, so I got to experience adolescent angst from the outside about a decade earlier than I'd expected. FUN TIMES!)
I do regret not having as much freedom to party and get drunk and chase loose persons. On the other hand, my offspring is (as any father will tell you) the most beautiful and charming child in the world, when I say "she's so smart!" there's a shudder in my voice and we have realised the important goal here is to steer her away from becoming the next Dark Lord. She likes hissing like a snake already.
In general, the most difficult task in my life has been to work out what I actually really want: what will satisfy me. Note I say "satisfy me" rather than "make me happy" - I'm much clearer on the former as a guiding principle than the latter. For many people, the hardest part of getting things done is to work out what it is they really want to get done - what their true goals are.
I once knew a couple who referred to their one year old daughter as the "evil overlord." I'm not completely unworried what happened to her.
So I found this post quite interesting:
http://www.gnxp.com/blog/2009/03/gnxp-readers-do-not-breed.php
(I'm quite sure that the demographics of this site closely parallel the demographics on Gene Expression).
Research seems to indicate that people are happiest when they're married, but that each child imposes a net decrease in happiness (parents in fact, enjoy a boost in happiness once their children leave the house). It's possible, of course, that adult children may be pleasurable to interact with, but it seems that in many cases, the parents want to interact with the children more than the children want to interact with the parent (although daughters generally seem more interactive with their parents).
So how do you think being child-free relates to rationality/happiness? Of course, Bryan Caplan (who is pro-natalist) cites research (from Judith Rich Harris) saying that parents really have less influence over their children than they think they have (so it's a good idea for parents to spend less effort in trying to "mold" their children, since their efforts will inevitably result in much frustration). And in fact, if parents did this, it's possible that they may beat the average.
(This doesn't convince me in my specific case, however, and I'm still committed to not having children).