Reminder:

Millennials are currently between 22 and 37 years old. The oldest have at least 15 years of work experience; the youngest have just graduated from college.

If you wish to discuss the current cohort of teenagers, the term you want is iGen.

Early Millennials are borderline Gen X'ers. Late Millennials are borderline iGen'ers.

For example, I was born in 1983 and can remember the end of the 80s, MTV with actual music on it, George H. W. Bush being POTUS, Gorbachev and the fall of the Berlin Wall. Late Millennials won't remember any of that, and might not even remember 9/11, since the youngest of them would've only been 5 years old at the time, whereas I was 18.