Some of the kids have, or are attending, college. The 20-year-old daughter (Jill?) is studying to be a midwife. I know it's not the kind of career that many modern young women would consider, and I'm sure if they said, "She's studying to be a nurse," it would be better received.
My niece decided she wanted a career in the Army. I would never choose that as a career (not that I have anything against the armed forces, at all!), it's just not for me.
Obviously, this is what she wants. At some point, she may want more. Maybe she'll want to be a doctor. I can't imagine her parents not supporting her.
ETA: Apparently, 6 of the Duggar kids are taking college courses:
http://www.examiner.com/19-kids-and...n-from-19-kids-counting-begin-college-studies
And please, let's not debate over online vs. brick and mortar colleges. My husband got his degree (via the military) from Park University, based in Missouri. His degree is just as valid as if he'd gotten it from Yale.