Must've been around 13-15, went to a pizza hut with my then girlfriend. I saw a darker skinner, heavy-set lady walking over to the counter with her two kids, all of them looking a little dishevelled. Without thinking I said "She looks poor" in probably a demeaning manner to my girlfriend, and she answered "you say that like it's her fault".
I'm dumb as fuck so the penny didn't drop until several years later about the reality of my privilege, and how unfair and fucked up the system really is. Nearly ended up alt-right, now I'm a comrade.
At the time it felt like I should be learning something but I just felt a bit ashamed, being nagged and all. Yk the saying, wisdom was chasing me but I was faster. Just needed my knees and back to ache for it to catch up. It honestly wasn't even age that got it to land. I just met people that didn't really go to the same places I did, or had a different idea of a hangout spot. I needed to see stuff with my own eyes to learn.
I'm slowly making my way through leftist theory, and introducing my equally-as-privileged friends into it, and have managed to change some of their beliefs which previously were set in stone. They're still liberal as shit, but at least now understand socialism/communism isn't just people trying to take their stuff.