I don't know, really..
I remember being a staunch anti-monarchist by about 8, (because I disapproved of hereditary positions!) and therefore refusing to stand for God save the Queen, which got me into a lot of ****, because the damned thing was a big deal back then.
Then, I don't know....perhaps reading lots of books about other people's lives in history and now made me think a hell of a lot was damned unfair? You know Dickens, Tolstoy, Cry the Beloved Country, American Civil Rights stuff....
I know I was having massive fights with my very rightwing father from about 10 on, and reading some Marx at 13.
I was slow to get involved re Vietnam, except in a very general way, but did by first year uni.
Feminism and Aboriginal Land Rights and gay rights were major issues.