You do realize, as a general rule, that the young are often the most liberal. Which condition often changes in the other direction over time.
No one has, as far as I know, endeavored to explain why. But perhaps it is that the life of a child is not governed by what they earn but by what is given to them by their parents. This mind set is likely altered by their entry into the world as an adult, but such surely takes time.
Many mock elections have been held in schools and the results are often far from those of the nation as a whole. Now based on today some may say that is a good thing, but I am sure many others would not agree. Think "Logan's Run"! Imagine if this idea had been successful during the Counter Culture Period when the mantra was never trust anyone over 30. And do not forget these folks are now running many of our institutions anyway!