The Iranians don't plan on stopping at 3,000, either. Despite their rhetoric about only desiring peaceful applications for their nuclear program, they built Natanz to run the much larger, industrial-size 54,000-centrifuge cascade. Their one uncompleted reactor at Bushehr would have no need for the kind of output produced by such a cascade for the less-enriched uranium used in power plants, but it would allow them to start cranking out nuclear weapons on a much more regular basis than once every nine months.
People used to say that we had years before Iran could build a nuclear weapon. Now we have months.