I have been watching anime a long time. Since about 1985 or so.
Despite the title above, the very very first anime I saw was not Dirty Pair. It was a butchered English-dub version of a Cream Lemon video. With the passage of time I honestly forget if I ordered that on a VHS tape via the mail, or picked it up while visiting a porn shop. Probably the former, as I’ve been in a porn store perhaps five times in my life; the atmosphere there is definitely not something I enjoy. Whatever the source, while watching that video I didn’t know that what I was watching was anime. So I don’t count it as The Beginning.