Iran is a country that signed an agreement (NOT) and now going against it, If we look at that perspective our vote goes down well against Iran. Compare this with our agreements , even after so many wars and loss of life we still continue to honor Indus water sharing treaty with Pakistan.
Even if US walks out we would still have strategic reserves that would help running the reactors, as a worst possible case we may have to return the reactors at current market prices. Which is fair.
Even after Testing a nuke, US is not going to terminate the agreement right away, it is still going to examine under what circumstances it has done so (The tests), and then only any action would be taken.
Well I think it is in our interest to go ahead with the agreement rather than get sidelined. This may also act as a precursor for us getting sensitive space and military technology.
With sensitive space, military and nuclear technology only Pakistan and China should be worried, Communists have joined these two to destroy India from within.