I hate seeing headlines like CBC's this morning in the wake of the US attack on Iran: "In Wake of US Attacks, Iran Faces Pivotal Choice: Dash to Build a Weapon or Negotiate".
Very little in the world of foreign affairs can be characterized in such simplistic terms. It's not "either/or", and in fact Iran has a number of options open to it that this ignores.
Does Iran already have a nuclear weapon? Officially the answer is "no", but that's inference based on the fact they have never openly tested such a device. On paper Israel hasn't tested nuclear weapons either, but it is broadly understood to have a cache of nuclear warheads. I don't have access to sources that could confirm or deny Iran's possession of nuclear assets. At this stage, they could easily run a "test fire" to augment their "negotiating position, or just to make themselves less desirable as a target.
The other aspect of Iran's nuclear capability is the ability to create so-called "dirty bombs" (basically a conventional warhead with a "surprise package" of nuclear waste wrapped around it). Those are trivial for any country with a handful of reactors used for power generation to create, and are potentially just as deadly - especially if detonated high in the atmosphere.
We also should not ignore the probability of Iran having covertly purchased nuclear weapons from other states. It's quite possible that they have weapons purchased from elsewhere.
Iran has many paths through which it could acquire nuclear weapons capability, not merely through its own program of development.
Much has been made of "we must stop Iran from acquiring nuclear weapons", but like North Korea, such threats do little to stop a country that is determined to develop that technology for itself.
Is this a "negotiate or else" situation? Not even close. Iran has many paths forward - it may choose to "negotiate", while concurrently "sprinting to build a bomb", or it may choose to reveal weapons it has already in its hands to make its "hand" stronger at the negotiating table.
Similarly, because there are significant religious components to this situation, we can also suspect that they may choose to go "scorched earth" and simply unleash the most destructive weapons they have on hand.
Of course, all of this is speculative on my part - I don't have any information not in the news media, and I merely infer from what I do see. By no means should we assume that Iran is "cowed" by recent events, nor do I see a willingness on the part of Israel's government to engage in any kind of good faith negotiations.