Technically Speed Racer was my first anime, though I wasn't aware at the time what anime was. It was just a racing cartoon with an unusual type of art style.

I think the first anime I watched on purpose was Dragon Ball Z, though I didn't much care for it. My best friend at the time loved it though, so now decades later I'm stuck with more Dragon Ball trivia than I ever needed or wanted, lol. Also my other option at the time was Sailor Moon and no. Just.. no.