My question is, what specifically is she doing? Her laugh is " too loud"? She makes dirty jokes? She jumps around and becomes physically "goofy"?
I think it's important to ask yourself whether she is being unfairly singled out because she is female. Is she doing things that would be no big deal if a guy did them, but are "unladylike"?
At her age, I would proceed very cautiously if you are about to head down the "telling her to be more ladylike" road, simply because that becomes a slippery slope into stuff like making her feel like she should not speak up in the classroom. But if she is doing specific things that would be bothersome from any gender (for example, physical goofiness like pulling people's hair), I think it is fair to point those specific things out to her and remind her to stop doing those things.
ETA: I mentioned "dirty jokes" above because I was trying to think of what would possibly make an adult pull her aside. There are teenage games like "seeing who can say the bad word loudest in public"...in some company that might actually make your daughter more popular (rightly or wrongly), but that would be an example of a behavior to tell your daughter to "think about the audience" first (maybe: okay at the mall, not okay on a church outing).