Its an interesting question.
There is certainly an argument for that being the case, in terms of younger people having far more of their lives ahead of them with government policy decisions affecting them for a lot longer than they would a pensioner.
However, i can see the other side in that it is problematic to suddenly exclude people at a certain age from having an influence on how their country is run.
Perhaps a sort of weighting of the votes for those age groups could be considered, but that likely will just open up many cans with many worms.
It is like Brexit. Only the 50+ age group voted to overwhelmingly to leave (could have been even higher, im just looking at these stats which just has four age bands -
https://yougov.co.uk/topics/politics/articles-reports/2016/06/27/how-britain-voted). If it was under 50's, remain would have won by a big margin.
Therefore people who are close to retirement or retired basically wanted to leave and those with much of, or even their whole working lives/best years ahead of them voted to remain. So the group of people for which the decision would largely not affect, decided that the group who it would affect were leaving the EU (when said group didn't want to).