As long as you've seen the original Gundam movie trilogy or the TV series, it should be pretty easy to follow any of the UC stuff. Here in the US, CCA was localized several years before Zeta and longer still before ZZ, yet I was still able to follow along. In fact, ZZ didn't get released here at all until recently, when RightStuf got the license to release all of the Gundam stuff on DVD and Blu-ray. I've still only seen a couple of episodes of ZZ myself and don't feel I've missed much. Not to mention the main UC series and movies were initially released in Japan long before many of the OVAs and were just as popular then.
That said, seeing everything in chronological order can add to the experience. It better fleshes out the plot and characters, fills in the chronology, and expands on the world building. I'm actually in the process of rebuying everything on Blu-ray and trying to do just that (well, I'm temporarily skipping a couple of the OVAs during the One Year War). I would also recommend watching the 08th MS Team and 0083 at some point anyway since they're really good. So if you're going to watch them, now's not a bad time.