"this very first" is correct and usable in written English.
You can use it to emphasize the first action or item in a sequence. For example: "This very first step is the most important one."
As I said, this very first invention of Moog and Buchla was around about '63, '64.
This very first example I thought about is the smoke detector in almost every house in U.S. today.
As this protein layer will mediate the interaction of the biomaterial with the living world, the consequent reactions will be highly dependant on this very first stage.
"We realized that this very first system that we put together was very much of a homemade, completely custom system," he says.
In some ways, however, I think that this very first screen performance, her Juliet, is the most purely seductive and the funniest of her screen portrayals.
Now the stringency of even this very first step, I think, is remarkable, because the business-as-usual predictions of temperature increase by the end of the century without the Paris agreement were about 6 degrees [Celsius].
