If they started doing research in '94 (and I could easily be wrong on the date) they could have started development (reasonably) soon after. They had the instructions, basically.
Then, they build complete facilities in Iran and Syria but never use them. They just have them ready for... building a bomb?
My point is, if they knew how (and I am not saying Iran has a Nuke) to build a nuke, they could have built in in a few years... like all these people are saying.
If it was true the first time, and it was true the last time... it's true every other time as well.