Last week, the Obama administration released ACA exchange enrollment numbers as of March 1. In comparison to expectations, the numbers are spectacularly lackluster. At the national level, the hope of the White House was that enrollments would reach 5.6 million by now, but so far only 4.2 million have enrolled. That doesn’t even come close to matching the estimated 5.4 million Americans whose insurance plans were cancelled because of new regulations under ObamaCare.

Most worrisome, however, is the small number of young people signing up. The great fear of the Obama administration is that not enough so-called “young invincibles” would sign up because a major requirement for keeping the exchange premiums affordable is for young people to join in large numbers in order to offset the cost of insuring older and sicker people.

So far, only 27 percent of those who have signed up are aged 18 to 34—far short of the 40 percent the administration said it needed. Compare this to the 48 percent of those who have enrolled between the ages of 45 to 64—a share that suggests premiums on the exchange will increase sharply next year.

Nationwide, only 25 percent of those who have signed up for a health care plan are between the ages of 18 and 34. Can the system bear the weight of the 52 percent of people nationwide who signed up for health care between the ages 45 to 64? This is the Achilles heel of the ACA exchange scheme that so many have warned about.

Taking the total number of Americans who have signed up for health care into consideration, the likelihood that the Obama administration will reach its goal of 7 million enrollees by the end of March seems farfetched. There are simply not enough people buying insurance on the exchanges—the result of a disastrous federal health care exchange rollout, exchange premiums that in many states are higher than they were before the ACA and come with higher deductibles, and a general lack of enthusiasm.

And for young people it’s no wonder. As the Texas Public Policy Foundation demonstrated in October of last year, premiums for young people on the ACA exchange in Texas are significantly higher than pre-ACA premiums on the individual market, and federal subsidies dry up for young, single people who earn more than about $29,000 a year.

In other words, the exchange plans are not that great of a deal for working young people. As open enrollment comes to a close at the end of this month, we’ll see just how much this group is willing to pay for the Obama administration’s idea of “affordable” coverage.