I'm guessing most people over 30 can not commit to a 3-year full time study, but it's weird indeed that they're not even allowed in.
You can go to community college; that is a legitimate choice; but 42 teaches you in a different way, one which 42 argues is more suitable for learning than classroom hours and lectures. And you miss out on some of that ambition.
Most universities and almost every community college has acceptance for a wide range of backgrounds. You can enter my university on a GED at 31 if you like, doesn't seem possible here.
I'm 43, and enrolled at Holberton School, which is project based. Granted, I'm only taking 2 years off, but by the time the 9th month rolls around we will be interning in San Franciso (and possibly around the World). Some of those internships are paid.