The Obama Administration has released detailed information about enrollment in the Affordable Care Act—not just how many people are signing up for insurance, but also what kind of people and what plans they are choosing.

What you make of the information depends, as usual, on your expectations.

The figure bound to get most attention is the age breakdown. Insurers rely on premiums from healthier people to offset the costs of people with significant medical bills. And young people are a reasonably good proxy for healthy people—or, at least, as good a proxy as we have right now. According to a recent study by the Kaiser Family Foundation, about 40 percent of the population that could enroll in Obamacare exchange plans are between the ages of 18 and 34. But, according to the government’s new data, only 24 percent of the people signing up for coverage are in that age range. In short, the people who have gotten insurance through the Obamacare marketplaces so far are significantly older than the people who could, in theory, be buying insurance from them.

But is that really a big deal? In Massachusetts, according to analysis from MIT economist (and Obamacare architect) Jonathan Gruber, younger people tended to sign up later.