Paula, for a good and authoritative essay on the reasons we wear hakama, check out one of the back chapters of Saotome Sensei's Principles of Aikido book. It's a short but really good piece.
And yeah, Asim may be on the right track: maybe you'd do better wearing yours higher, or more rolled in, so your feet would have better clearance. As you get more comfortable in it you can lower, perhaps. I know a dojo where the Sensei does all the gi/hakama ordering for his students, and there are certain folks whose first few hakama are much shorter than they would expect, but Sensei wants them to minimize the effects of their clumsiness factors while learning to wear the things. Not saying you're clumsy, i don't mean that; just giving context for advice.