When is Baby "Ready" for a Big Bed?

Ikaika seems to be the kind of kid that, if given the freedom to do so, will let us know loud and clear when he's ready for something new.  This has been the case with eating, weaning, using the potty, and moving out of the nursery at MOPS.

Previously, I said that we were still a month or so away from trying the twin bed at night.  Last week, after going through the bedtime routine of jammies, teeth brushing and diaper change, I said to my son, "OK, time for bed".  This usually means marching into his bedroom and waiting next to the playpen.  This time however, he jumped up from the floor, trotted into his room and climbed into the twin bed.  Mr A and I stared at him, dumbfounded, as he snuggled into his pillow and waited patiently for one of us to come say prayers. 

I was honestly stunned.  For a minute I didn't know what to do.  Should I put him back in the playpen?  He's not "ready" for this, right?  Shouldn't I be the one who always knows what's best for him? It's always a little jarring when Ikaika's development is out of sync with my schedule. But, it's hard to argue with the logic involved here.  If he's getting into the bed without complaint that must mean that on some level he is ready to move on from the playpen.  At this point, arguing with him or forcing him to regress (when my goal is for him to get into the big bed eventually) would be counterproductive. 

So he's sleeping in his twin bed now.  Yesterday I packed up the playpen and stashed in under the sewing table where it waits for the new baby.