I can identify with you, I worked for a few months in a REALLY conservative environment. I'm an atheist libertarian with tattoos, etc. I had to listen to a lot of racist, homophobic, xenophobic talk similar to what you hear. I totally get it. Here's some advice:
1. Really assess how important it is to "fit in" with the group and if so, how much. The older I get and more experience I get in nursing, the less I give a fig about "fitting in." I show up on time, do my job well, politely say hello and goodbye, keep my mouth shut, don't rock the boat, help others where I can, go home and leave it there. You're not there to make friends. You're there to do a job, take good care of your patients, be a team player (professionally) and collect a paycheck. You can still be polite, smile, say hi, talk about the weather, whatever, without being a stuck up snob, or detached. I have been lunching alone for years, and don't give a rip. I have friends and a life outside of work.
2. If they really pressure you to engage in these conversations, consider learning more about these people and the way they think. Part of the reason this country is so divided is because of this "us against them" mentality so many of us carry. These conservative people are just people, and likely products of their environment just like you are. I am neither right or left, (yet totally both) and frankly, I consistently see liberal/lefties having a harder time relating to their counterparts than the other way around. You can engage without being oppositional. I have friends who are super right wing conservative, and also some mega lefty tree huggers. I love both equally and completely understand why they think the way they think, even if I don't agree - and respect the crap out of it! Because I took the time to learn where they were coming from.
I understand it's repellent when they present themselves so disrespectfully. You can pick your battles. Choose to detach and let it slide, or engage with curiosity. Or your 3rd choice is to stay angry, stay passive, be resentful, and stew in rage. If you're new, I'd be very careful about any reporting to management about this. Might wanna keep it on the DL for now.
As for your appearance and age......well, at 33, you should be used to this by now. If you're as little as you say, being called "kiddo" and mocked for your looks/size should be old hat for you now and your coping skills about it well developed. You are too old for this to be anything new.