Old internet culture? Since when is 4-ch some sort of stagnant museum for "old internet culture?"
It's old enough to have been part of old internet culture, sure, but this is a discussion board, not a nostalgia page for old memes. We have years worth of original 4-ch culture, some of it is very old, some of it is relatively new.
I see no reason why younger users should be discouraged as long as they contribute quality posts. I am personally aware of multiple younger users in the textboard community who I would consider quality contributors.
You, >>16, do not contribute quality posts irrespectively of your alleged claim to old age.