John Doe said
Book a room at a nude resort for a holiday and take her there. Many girls have an inner exhibitionist that will come out with a bit of nudging.
  

As a girl with a very outer exhibitionist, I'd say a nude resort might be a bit much for a first timer. A holiday is a good idea though, since it feels like you can do stuff you wouldn't do in your normal everyday life. It has that feeling like it's not really real and is completely separate from your life back home.

It'd feel very different to hear your boyfriend randomly suggest going to a nude beach you live near (which sounds crazy because you're in normal everyday life mode) versus him cheekily suggesting trying out the nude beach near the hotel (which feels like a fun thing to do while on holiday).

In my opinion, a nude resort would be a bit full on and in her face (and you'd 100% have to tell her before you went, so she has to agree to it while in normal life mode). But if you book a hotel and there just happens to be a nude beach nearby, then you can suggest it and she's free to decide whether she wants to try it out or not.

bitsnbobs said
You need to assass how comfortable is she with being naked in private as well. Does she sunbathe topless, for example.
 
Definitely not a naturist holiday - maybe eventually, but not at the start. Possibly suggesting skinny dipping to break the ice. That can be done without even a nude beach.
  

100% agree with this. At the end of the day, she has to be up for it first and foremost. You should be aiming for her to become interested in ENF stuff and comfortable doing it. Surprising her with a resort full of nudists probably wouldn't have the desired effect. She has to opt into it herself out of her own curiosity.

Making it private and easy for the first time is a very good suggestion. It's probaby a good idea to find a secluded place for just the 2 of you to skinny dip together (where she can feel confident nobody else will go to), or something fun and intimate at home (like being out in the garden).