How do I avoid people talking to me on the street or the park?

I(23m) have been struggling with different mental issues for years but I am working on getting better. I have started going outside and taking walks(10k steps today). Before that I could go weeks or months without seeing sunlight.

I noticed people would just hit me up for a quick chat asking me where I’m from. Maybe I looked like a tourist and looked lost or something but I was just looking around. I don’t really want to talk to them to be honest. At least I’m not ready yet. I just wanted to walk around and just enjoy my music. What’s a good way to tell people I’m not up for talking. I can’t look intimidating because I’m not a big guy. I already have 2 airpods in my ears as well.

Also I get very self conscious about my look and I feel like people are looking at me. Like I would think maybe I smell bad or I look weird so I would ask my friend if I look alright which they would say I look fine but I’m not sure if they were just being nice. And sometimes I feel like people are talking about me like if they are talking about body figures I would assume they are talking about me. How do I get rid of these anxieties? Any help is appreciated.

Edit: someone told me to get a resting bitch face but I think I have a pretty okay one so if it’s not working and I have to try hard then it’s not resting anymore imo.