So much for younger millennials being more Republican than older millennials.
In all fairness, this is Trump we are talking about. Young people hate him. This election is going to be hard on electoral trends analysis, as an awful guy like Trump may turn people against himself/the GOP short-term purely based on a large repudiation of him, masking the actual trends occurring below the surface.
Or it could turn out that Trump will have single-handily reversed any pro-Republican trends in the youngest demographic cohorts. At this point, who knows.
Most political science studies suggest this point will be the case. Studies have shown that those who vote for the same party 3 cycles in a row will be locked to that party for the rest of their lives (baring major changes). Most people form their lifelong political view points during their teens and twenties. So to most young folks voting for the first time this cycle, Donald Trump is to them as George W. Bush was to my voting cohort. Therefore it is entirely possible that Trump will push younger millennials to be just as Democratic as older millennials.