Relax, my wife was the same way. We arrived, went to the party pool, she watched everything going on around her... She lasted about 10 minutes. The top came off and hasn't came back on since.
I was trying to close a business deal and was using my phone to email. I finished, set the phone on the umbrella table and moved 3’ to the pool edge. Maybe a couple of drinks, friendly eye candy and I was distracted. Turned around and no phone! Stooopid! Now I take a backpack, strap to chair, no problem! Be vigilant and smart. You’ll be OK.
Never push the topless thing, just makes them defensive. If she wants to go topless but needs to work up to it this May work. Lay on front and take the top off. Then as the comfort level increases, propping up on elbows allows for gradual and measured exposure. It comes fairly easily. I helped with the process and it went very well. The fact that gals are flaunting them everywhere doesn’t hurt. Take a t-shirt for easy no problem cover.