We are so uncharacteristically bad at judging based on age.

It’s most obvious between a parent and child.

/grey - terminally ochain dad & spouse, building products on frontier solutions w frontier people.

Evangelizing Incentives That Combine Self Interest With Collective Benefit & A Few Other Things I'm Still Trying To Figure Out

The many times I try to prevent my 3.5yo from doing something because she’s 3.5, no matter how many times she surprises me on the upside, when I don’t limit her via age. 

IMO, this holds true throughout all of life.

Yep, assume they can do it, stretch them, be cognisant of the risks and provide a backstop. They will surprise themselves and you.  They will gain confidence.  I think we overprotect and over-celebrate easy tasks (rather than stretch tasks) which hampers growth.