I've competed in bb, but the girls are right. I've come across alot of girls who decide they want to compete because they are swimsuit models or strippers or whatever. Definitely understand that this requires "some" training. Though they are still trying to figure out what exactly they really are looking for in judging, this category has now been around for a year and a half and its already starting to head in the "hardcore" direction of fitness & BB. No you dont' want to be ripped up w/ 17" biceps & striated glutes, but you still need to be lean and have some muscle. But they are also wanting those who are extremely "photogenic" and have the boobs, etc. Just a nice beach bod ain't gonna cut it. By the same token, former FBBs who didn't want to train as hard as required for BB also suffer because they come in too big & hard.
Definitely go see some shows to see what exactly figure competition is and see who are the girls competing and who wins. That will give you an idea of what is expected. Also because there are many competitors in this category, it does get very competitive so if you dont' know how to pose, etc. forget it. That just tells the judges you didn't come prepared. Find someone who can teach you the posing. It will make the difference and give you the confidence that you know what you are doing.
One last thing I wanted to add about the organization that you choose to compete in. NPC is not necessarily "natural". They have "tested" shows (they test via voice stress analysis or lie detector usually) but there are still plenty of people (men & women) who "cheat" and juice. And the non-tested shows, well... most everyone juices. So keep that in mind - the girls who are serious about figure comp are probably doing some anavar or something --- so set your expectations accordingly. I'm not saying you need to juice or that its wrong or anything like that -- just giving the reality of competition.
Go for it! Competition is a kick!