Here we go.
Pictured above is Weird Al Yankovic. Weird Al is 56. Weird Al can also kick over his head, run back and forth on a stage making upwards of 20 costume changes, make jokes, dance, and sing on key all at once. That's good, not just "for 56" but "for" anyone.
My experience is that people of all ages can do great things, and it's important that we all know that. That way, if we're 30 and we feel like we have no idea what the hell is going on with our lives, or we feel stopped along the way somewhere, or whatever, we know that some people's careers and lives are just beginning.
If our nephews, nieces or sons and daughters see a 13 year old start a business or a 16 year old graduate college, they know the sky's the limit for them, and they can aspire to big things now, instead of just wishing to be older.
I've seen the ageism on both sides- people talking about how everyone "millenial" or whatever they want to call the generations below them are lazy, overprotected special snowflakes who can't function when anyone doesn't like them or their Facebook status, and I've also seen a young office turn on their older staff, mock them for their out of date ways, and basically drive them away, though they're perfectly talented and qualified for the job, and might even have some insights and ideas that would blow their minds.
Mozart started composing at age 5
I just read about a kid who summited Kilimanjaro at age 9.
J.R.R. Tolkien published the first of his Lord of the Rings Series at 62.
Einstein got a nobel at 42.
So why can't we just throw the numbers out and start realizing that a lot more than we think is possible. Time to start trying that.