[JohnsonB]

Because the metric is excellence. Realistically, you can't expect a 14 year old to produce something of the quality from someone with a decade more experience, all else being equal. But if they can produce something that is uncommonly ahead of your time, then you have a case for showing it off based on that fact, and it benefits the community to reward skill as early as possible and give people the opportunities that "fame" affords.

[citricsquid]

Age doesn't reflect on experience. There are 15 year olds that have half a decade of experience developing and there are 30 year olds that started last week.

The people that upvote "I'm 15 and this is my new app..." probably aren't going to upvote "I'm 30 and this is my new app..." but the latter could be a more impressive achievement.

[dakimov]

Yep, that's called age fascism.

[YuriNiyazov]

"Fascism" is a little strong, don't you think? "Discrimination" is probably more appropriate.