First off, don’t disclose what you have! I’ve made that mistake to some extent, and gotten that exact response!
The best way to ‘test the waters’ and/or introduce the idea of preparedness is to discuss what natural disasters are most likely to occur in your area. For us, it’s bad weather situations, both summer and winter. We’ve been through both. Learned lessons the hard way. Power outages are common in our area. That’s another conversation starter.
Everyone knows someone who has unexpectedly lost a job, or faced a medical emergency (both of which we have experienced). Say a friend you know just lost his job, and you are discussing it with other friends, talking about how you could be prepared for that (not giving details of how you are prepared obviously) could plant a seed in someone’s mind.
Realize that ‘normalcy bias’ clouds most ppl’s attitudes. It even affects preppers!
I actually have adopted more of a ‘homesteading’ attitude vs. a ‘prepper’ attitude. Homesteading and prepping are different but not mutually exclusive. You will find that a lot of homesteaders are indeed preppers, but ‘shun’ the prepping term because of all the negative press. I have found some great friends and connections in the homesteading circles who are also preppers. Perhaps look at joining local homesteading groups. I am not self promoting here, but I help run a state centric homesteading group. Check FB/social media for something similar for your location. You might be surprised what you find! Social media groups in your area related to homesteading, gardening, livestock groups, self sufficiency.