No it is not.
The concept '''impossibility'' has no meaning, nor does the concept even exist without it's opposite concept in relationship to itself. The connection is born of ''thought'' by association as each and every 'thought' is triggered by the preceding 'thought' creating the illusion of a ''knower'' existing as a continuity, even though this ''knower'' is just a strawman mental narrative known as knowledge. In reality there is no IDENTIFIED knower.
Therefore,conceptual opposites have to exist in the exact same instant, else, nothing would make sense in a conceptual knowledgeable way. Each opposite defines the other, else neither exists...so both ideas have to exist at exactly the same time in supposition.