It's strange to see how these days people in their twenties are expected to behave like adolescents. There was a recent NYT article gushing about how incredible it was that Obama's speech writer was only 27 whilst his peers played video games all day. By that age Darwin was already back from a five year voyage collecting samples and Einstein had written a paper on special relativity.
Luckily the HN community expects us to do something worthwhile regardless of age.
I think work age is slightly different in Asia. Most people do not work till they have at least a BS Degree (21/22) or possibly even a Masters degree. And also, while they are in school/college they pretty much stay at home in the comforts of their family unless they go for an engineering college to a different city. So, indirectly they are pretty much protected from the real world issues for a major part of their youth. So, age/maturity also seems to have some cultural flavor to it as well.
Also, I really don't understand why this should be a job for some _manager_, who doesn't even need to ever see the phone, and not the engineer who needs to work with them. Managers are more important and trusworthy than engineers? Oh. Why.