Call them the junior boomers. They are baby boomers, certainly. But they didn't come of age in the 1960s. Some weren't even born when that decade began.

Junior boomers are those born in the second half of the generation, from 1955 to 1964. There are 41.8 million of them, says the Census Bureau. And while their older siblings are becoming eligible for Social Security, junior boomers face much more challenging retirement realities.

For one, they got slammed hard by the Great Recession. Their average net worth was nearly halved, from $172,400 to $94,200, according to the Center for Economic and Policy Research. Furthermore, junior boomers live in a world where pensions are disappearing and Social Security's future is debatable.

"They need to invest fairly aggressively in the 20 working years they have left," says Paul Escobar, senior vice president and wealth and retirement specialist at Bay Colony Partners in Woburn, Mass. Escobar says he does not think early retirement will be an option for most junior boomers.

There's cause for hope, however. These steps can jump-start junior boomers' retirement planning, giving them a shot at catching their older siblings.