That's a common misconception. People don't become more right-wing with age, people become more right-wing with wealth. Turns out if you have a lot of personal property you suddenly are a lot easier to convince that you deserve it and others want to take it away.

The good old "if you're not a liberal when you're young, you have no heart; if you're not a conservative when you've grown up, you have no sense" is just a way to morally justify a political shift that happens to align with a change in financial interests, nothing more.

EDIT: Here's a source since people seem to downvote based on their feelings: https://www.insidehook.com/article/politics/millennials-voti... It doesn't outright say the difference is wealth but it does say the expected trend towards conservativism doesn't present in Millennials to the same degree.