Statistically sound?

The author Ian McEwan has come in for some stick for suggesting that, if there were to be a second rererendum on membership of the EU in a couple of years' time, the result might be different.  His premise is that in the last vote it seems the younger you were the more likely you were to vote Remain, and the older, the more likely to vote Brexit.  So in two years time there will be "... 2.5 million over-18-year olds, freshly franchised and mostly Remainers [and] 1.5 million oldsters, mostly Brexiters, freshly in their graves".  And this, he reckons, would be enough to swing the result the other way.  He may be right, but I am constantly surprised to find that my generation mostly voted Leave.  I make no bones about it - I voted Remain, and did so on the basis of "better the Devil you know" - I was not prepared to tale a leap into the dark, and I was and still am amazed that others in my age-group clearly did not feel the same