What are the options on a second Brexit referendum?

The people who voted for Brexit are dying off

Question: What are the options on a second Brexit referendum?
Position‹3 of 6›: There should be a second Brexit referendum
Argument1 of 3›: The people who voted for Brexit are dying off

A natural demographic shift has taken place. By January 2019, even if nobody changes their mind, the country will be pro-Remain.

The argument

Given that older demographics overwhelmingly voted to leave the EU, and younger demographic largely voter to remain, the mathematics behind the nation's demographic shift dictates that in January, Britain would no longer be a pro-Brexit country, even if nobody changed their vote. The mortality rate in Britain shows that the oldest demographic in the UK is dying off at a rate that cuases the number of Leave voters to shrink by 1,350 per day. Combine this with the two million voters that have reached 18, the legal voting age in the UK, since the 2016 referendum, and by January 2019, statistically, the UK will be a pro-EU nation.

Context

By January 2019, even if nobody changed their mind and everyone voted the same way as they did in 2016, the natural demographic shift of the UK would naturally mean that a second referendum would return a remain vote.

Premises

[P1]Older voters who backed Leave are dying at a rate that shrinks the Leave electorate by some 1,350 a day, while around two million young, Remain-leaning voters have reached voting age since 2016. [P2] This demographic shift means that, even if nobody changed their vote, Britain would statistically no longer be a pro-Brexit country. [C] Therefore, because the Brexit majority has eroded, there should be a second Brexit referendum.

Counter-arguments

Our democracy relies on the results of a nationwide vote, administered at a specific moment in time. Even if the demographic changes hours later, it is not practical or reasonable to expect that we should override the outcome of the vote because of a demographic shift. The outcome of the vote was final. It must be respected. Otherwise, how often do we have to have nationwide elections? Every year, to account for shifting demographics? Every six months? Whenever there is a significant demographic change? This is not practical.

Rejecting the premises

The demographic shift is irrelevant. The referendum accurately captured the will of the people in 2016. It was, therefore, legitimate. Therefore, the results must be respected.