When someone tells you that you should "not yet be worried" or that you should "maybe" be worried, it's the same thing as telling you to worry. You should prepare for worry-which amounts to worrying about being worried.
Of course we should be concerned about any new strain of flu, especially one we know very little about, but the media (and, okay, I'm the media) and Twitter (and, okay, I'm the Twitter) are fueling hysteria. Unless you are a public health official, or hospital worker, you need to just go about your business the same as ever. And if you fall into one of those former categories, you should be taking precautions and preparing for emergency situations--but you still shouldn't be worried.
A personal digression: I hopped on a plane for South East Asia the day after the Bali bombings. I headed right into the maw of what the popular news media and public opinion was telling me I should avoid. During the six months we spent backpacking there, we caught Dengue Fever, which is a pretty nasty mosquito bourne illness. By the time we were getting ready to leave to fly back to the States, SARS was a full-blown media clusterfuck. Everywhere we went in Bangkok in those last few days, we saw people wearing surgical masks. The case fatality rate was a stunning 9.6 percent. We received frantic phone calls from the States urging us to get on a plane now, to fly back now. To get the fuck out. We did not. The interesting thing was that we did not panic, or come close to panicking, until we saw the Western cable news industry in full effect in the airport in Bangkok. Our flight to Tokyo was filled with hacking, coughing, disease-spewing people. We, in fact, asked to be moved from our initial seats, located immediately behind a passenger who had a wet, productive cough and sneeze. It was wise for us to leave when we did (and of course we were planning to anyway). But there was never a cause for us to panic.
We as humans are hard-wired to worry. We evolved as thinking creatures given to assessing and reacting to not only immediate but also long-term risks. Yet I think in the West we tend to lead such comfortable lives that we allow much nonsense to trigger our natural tendencies towards risk aversion. The things we should truly fear (heart disease or obesity, for example) we tend to ignore as they are constants. But something new comes along and, blammo, there's a run on dust masks at your local Walgreens. Now, clearly a novel strain of flu is something some people should be worried about. But the odds are you aren't those people. Those people work at public health agencies; you more likely work at a public relations agency.
When it comes time to worry--rather, if it comes time to worry--that signal will be loud and clear. Until then the thing to do is to be educated about what's happening, wash your hands and take other sanitary measures you should be taking anyway, and go about your daily business as usual.