Probably both. I did a couple from TypeLogic: Type-Related Links, the one on okcupid, and one on mypersonality.info. So yeah, no paid tests or anything.
People have always told me I'm mature for my age. Well, at least since ~10 or so. I suppose marrying my high school sweetheart (and not because of an unexpected child, which everyone who didn't know me would ask *sigh*) might be evidence to support that as well.