(It's called "Blog for many of the days of June, right?)
My first paying library job was, I think, when I was 19. A couple of years before that I had a week's work experience in a library.
But my first library job I don't even remember. I assume I had one because I was going through some old stuff from high school a while back and came across a "Library" pin. I don't think they handed those out just for borrowing lots of books. I guess I shelved? I can almost remember shelving -- or possibly browsing, but I think it might have been shelving. I may or may not have checked out books.
I do remember, with a friend, working out that if you held two books together in a certain way you could cancel out the security strips and get them both through the security gates. (Should I be saying this online? Ehhh, it was a long time ago, surely they've fixed that problem by now.... Also I don't think we got it to work every time.)
I also remember my first introduction to an indexing database. I used it to look for articles about Star Trek: The Next Generation and interloan a particularly interesting magazine article. (Previously my geeky scrapbook had contained only the snippets I could find from the Press and the Listener -- I had whole seasons' worth of the little plot summaries from the TV schedules and was always excited when they published a photo of one of the characters to go with it.)