The 21st Century doesn’t start tomorrow or a week from now. It started several years ago.
This is a narrow and vastly optimistic view of the present situation. Of course "centuries" are arbitrary constructs, but if you think the next 92 years are going to be much like the last 10 or 20 or 30 you're being very sanguine. It is going to be a few more years before we really have a sense of whether we should be preparing kids for The Long Emergency, The Singularity, both or neither. Could someone in 1908 know how to educate students for the rest of the 20th century? Yes, because there are timeless principles, but not in the sense of making policy based on predictions about the future.
Ultimately, the issue here is that "21st Century" whatever misframes the question, so you get stupid answers.