As it turns out, your mental picture of a Millennial is entirely incorrect. If you thought that they, like their great-grandparents, often live on farms, go to work out of high school, and are overwhelmingly white. Not sure why you thought that, but you were incorrect.
Pew Research put together a nice little interactive that compares four generations. There are the Millennials (born between 1981 and 1996; younger people are from Generation TBD), Generation X (1965 to 1980), the Boomers (1946 to 1964) and the Silent Generation (1928 to 1945). It's important to bear in mind that the metrics below depend heavily on those year demarcations, which are themselves often up for debate.
The graphs below compare each generation in the same age range, 18 to 33. (The Pew site has overall metrics.)
Trends trend, so it's not a huge surprise that the increases in the non-white percentage of each generation and in those never married has continued pretty steadily. The generation is approaching half non-white, the plurality of that group being Hispanic. Like most of the country, they're more likely to live in cities than their parents/grandparents were. (Most of them ended up moving to cities, for what it's worth -- or saw their non-urban areas become urbanized.)
Only 28 percent were ever married, compared to 64 percent of the Silent generation in the same age range. That may also be linked to this bit of data.
Millennials are better educated than previous generations, which would naturally postpone marriage. It's also in part why they're less likely to be part of the labor force than their parents/grandparents were, though the post-recession uptick is visible here, as well.
Do we need to explicitly explore the political ramifications of some of this? We're going to assume not. Perhaps the most interesting question, though, is what the next generation, those just starting to be old enough to vote, will look like. A hint: Trends trend.