firts impressions
My wife & I were first timers, at a CO resort, this past summer. My wife was a bit uneasy, not knowing what to expect. After we set up our tent, we undressed and sat in our lawn chairs to relax, I was returning a phone call from our neighbor and a guy passing by started talking to my wife. Her first thought was;' Oh, great! Here's the first creep, wonder how many more there are.' To her surprise, this man was very polite & friendly and looked her in the eye when he was talking to her. After approx. 1 minute of small talk, he was back on his way.
That is when she realized that we were not surrounded by weird people, and that she was being treated the same as if we were in any other (textile) campground.
Safety.
My wife's first-time at a nudist resort was pretty stressful for her; as she did not know what to expect. Our first encounter was with the "lady in a sarong behind the desk" at check-in; who was very cordial and fun. She explained the resort, without going into any "expectations" of nudity; which made my wife feel like she wasn't going to be/feel "forced" to be naked. We then sat outside the pool, me naked and her in a cover-up; and the few passers-by greeted us as they walked by, which made my wife feel like she wasn't going encounter any "weirdness." So her first impression was that she was going to feel safe there. Safe enough to "take the plunge" and get naked too.
Once naked, she saw that people weren't staring; as a matter of fact most only gave her passing, friendly glances. Which motivated her to start conversations. At which point she realized that she could actually have meaningful conversations with complete strangers; without any self-consciousness. That motivated her to fully embrace the situation and her own nudity.
I'd say potential "deal-breakers" would be the opposite of what my wife experienced; and has been known to sometimes happen at nudist resorts. Like "the lady behind the desk" being unfriendly and/or stressing the "necessity" to be naked a little too insistently. Sitting outside the pool area and people giving my wife "snarky looks" because she's not naked. Getting finally naked inside the pool area and someone looking at her a little too "hard." Any or all those things would have probably cut my day short.
I generally explain nudism to people that it's exactly like the normal world except nude. The exact same thing except people just enjoy not wearing clothing. Absolutely everything is the same, you wouldn't act any differently than if you were dressed in your neighborhood or at work. Boundaries and courtesies and manners are all the same.
For first timers, I would aim for a low pressure experience. No pressure to disrobe or be put on the spot. And a place with a good gender balance, particularly if it's a new woman. Avoid the occasional creep (at legit nudist places there aren't many) at all costs as that will form an inaccurate and unfavorable impression. I agree with the other poster, safety and comfort.
The first time I brought a friend to the beach here, she was new to nudism, we struck up a conversation with a couple there. It was nice. But then at the end, when we were leaving and clothed, the guy asked to take her photo (and not mine, or ours together, specifically just her). It was so awkward and creepy. I was upset that he gave her this impression. First timers especially want an assurance of privacy generally.