Hard to tell if she will join at this point. Here is a formula that can used in deciding if a character will join the Crew.
1. Luffy asks them, and they refuse.
2. Character has a tragic past involving a flashback. Usually the tragic past involves the loss of a mentor.
3. Character provides a skill the Straw Hats need.
4. Character has displayed some fighting skills.
5. Character has a strong dream. The dream is probably the most essential factor.
Now these are more guidelines than rules. Robin for example didn't have flashback until after she joined, and the Straw Hats didn't express a need for an archaeologist, Luffy never asked Franky to join when they first met, and Brooke actually accepted Luffy's offer on the spot.
Now of these Camie is hinted at having a tragic past. She could always have a flashback, and a strong dream revealed later.