It's never too late--once an alum, always an alum! You can make it extra-special by getting it in DZ colors.
I'm still debating about whether or not to get a class ring (I graduated in May). I wore my HS class ring until the fall of my junior year, when I got a very special ring from the boy.
It's $450 or so, which can be spent on better things right now. Maybe in a few years.